Or are my elderly mum's neighbours?

There's no maximum height for deciduous hedges, I've got a 10ft one between one neighbour and the other side must be 20ft at least. The high hedges act only applies to hedges over 2m if they are fully or almost all evergreen.
It's not illegal to cut hedges at any time of year but it is illegal to disturb nesting birds so you have to check for nests before cutting. Much safer to wait till at least August when they will have fledged.

Actually I'm pretty certain that there is no legal height for hedges, but that as a general rule a 2 metres is considered perfectly acceptable. The 6ft rule applies to fences. Or it used to be 6ft. It could now be 2 metres.

I do not believe this to be true. I believe that it is 6ft, unless this has changed recently. In some developments and estates there are some restrictive covenants which may restrict hedge heights. This could apply to some council accomodation.

Re trees/hedges there is high hedges legislation, but if 5 ft, then its well within the regs. The regs are there to protect amenity value (enjoyment of ones property but not views) as well as to allow adequate light in. Re amenity value, the hedge would have to be imposing and close in a way that ruins them living there.

I don't believe that there is any legislation against cutting hedges during nesting seasons, only wildlife legislation to protect ground nesting birds (The Wildlife Act 1981).

I would install cameras if it makes your mother feel safer and get her to save any letters from them and date them. Other than that she is best to ignore them and not interact at all.

Which UK law is this, please? I can't find it and it'd be super-helpful re our neighbour's hedge.

That's the same thought that'd I just had
How nasty to be bullying an old lady.

Nonsense.

OP if you put up ring door bell or other camera just be careful what you take videos off. Make sure the images don't go further than her property boundaries. If she has high hedges and fences that shouldn't be too hard to do.

Also put a (small) sticker somewhere on the front that the house has CCTV.

Otherwise the neighbours will accuse her of harassing them with her camera(s) and they will probably win any argument as they can go to her HA to complain.

That is only true for farmers and landowners. There is no such restriction on cutting domestic garden hedges. Otherwise people couldn't have those ridiculous topiary arrangements.

There is an exception to the rule (but an agricultural one, and informal) that says pigeons are fair game but only because they breed repeatedly year round. Pigeons are charming, but there are far too many of them, and they outbreed almost every other species, so their numbers need to be controlled. The breasts are really delicious to eat, but put the rest of the carcass in food waste

Harassment of elderly people is a crime. Please ring the police again and tell them they are harassing an elderly vulnerable person.

My mum had a crash and someone was pressuring her to pay for the damage as they didn't have gap insurance. They said they were going to come to the house within the house and speak to her. I rang the police as I was unable to get there and they went straight round to him and said if they go near her house they would be arrested.

My mum never heard from them again and the insurance went through as normal. The police were very good.

You are quite right @Spirallingdownwards
theres no maximum height limit for a hedge on boundaries.

OP. They cannot force your mum to cut her hedge.
She is not legally obliged to do so.
If the neighbours want to take the matter to court the amount of overshadowing will be considered. It doesn’t sound like there’s excessive height or overshadowing and fake grass 🤢doesn’t need the sun.

My mother had an issue with a difficult neighbour always reporting her to the police for ridiculous things. In the end we sent a recorded delivery letter to them telling to cease and desist her harassment or you will be taking legal action. I’d also get a ring doorbell and state that n the letter - that you will be recording and documenting all incidents of harassment or bullying from this point forward. It did work with my mum’s neighbour.

What are you on about ?

There is a high hedges act. However no way would you net the criteria. It’s worth a read. You could even print off and highlight and use as evidence why it’s fine to them. Good to know the criteria. There’s an ‘over the hedge’ section that could be useful as that’s the approach they should be taking.

https://www.gov.uk/government/publications/high-hedges-complaining-to-the-council/high-hedges-complaining-to-the-council

like they’re just being bullies. Maybe make a diary and keep the letters and take photos of the garden and hedge for reference purposes. Quivering if there’s grounds for harassment. No harm in revisiting with HA/police. There is the nesting season rule where she’s not be able to prune either.

Your poor mum.

It's hedges with nesting birds under Section 1 of the Wildlife and Countryside Act of 1981.

When in doubt you presume there are birds there until you can prove otherwise

I lived in a house share with lots of hedges and we had to wait until the middle of kids school holidays in England before we cut them back. There were actually nesting birds in two of them.

One of my friends also had high hedges. They don't cut them back until August every year.

Sorry if I am repeating previous posts, but the law is quite explicit that cutting back hedges and trees after March 1st is forbidden. Cut back between late October until 28 February is fine. From March 1st, no. You must wait until the end of September. The rule is to protect fledglings. We have hordes of them in our garden now. Learning to fly and practising landings. Working out how to get on to the feeding stations, and where to peck. And in a few days, we're taking the bird table away so they learn how to feed themselves during summer when food will be abundant.

Could you complain to the HA about the neighbours on your Mum's behalf? It's bullying and abuse of an elderly lady who just wants to enjoy her garden. Your poor Mum.

You need the
police (Neighbourhood team) to go to the neighbour. They are plain and simple bullying her and that is anti-social behaviour, causing fear, not sure if it’s a public order offence (possibly if outside).

I don't think this information is correct.

It really is not illegal to cut hedges until the end of August. Where on earth did you get that from? This site is truly insane at times

Exactly. Most solicitors charge £300 + per hour and certainly don't send letters out for free. I know as I've worked in law for many years. OP your neighbours have no redress at all. Your mum needs to either ignore them or go back to the HA and ask them to deal with it. She is in no way in the wrong here

Your poor Mum shouldn't have to put up with these feckin' bullies.
We bought a Dekco security camera from Amazon after some anti social behaviour on our close, I think it was £30. It is set up so you can see it on your phone and you'd be able to keep an eye on your Mum.
It's good for evidence, even the police officer who called about our complaint said the picture quality was brilliant.
Hope things improve for your Mum, and she gets to enjoy her garden again.

The 1m rule only applies to walls and fences as they are development under the Planning Acts. Growing plants does not count as development and there is no restriction on height.

The High Hedges legislation only relates to evergreen species, or where a hedge is mostly every. It only comes into force for hedges over 2m (6'6").

Just tell her to ignore and put a ring door bell up

If they come round and proceed to intimidate her, she should complain to police about harassment