Weird neighbour behaviour what do I do

I would innocently ask the neighbour what they were looking for in the garden. If they deny it mention the camera. Stare them out until they crack!

My advice is say nothing and keep a recording and a close eye on neighbour for a while. Then go to police if needed.

I like this idea

Also anti-vandal paint on the fence?

I would find that deeply disturbing. Definitely never, ever give him a key- strange that he even asked! Maybe keep quiet for now and keep recording. How often do they go away?

I would contact he police and leave it in their hands. He sounds pretty creepy. Once he knows that you have cameras and aren't scared to involve the police he will probably move on to someone else.

This sounds incredibly strange and really unnerving. They should call the police to ask for some advice and ask that this incident is noted down to help any future action should they need the police later down the line. I'm torn between approaching the neighbour and not to be honest.

Ask him, you were seen on camera on our property, was there an issue we should be made aware of.

I would speak to non emergency police to ask for advice. How unnerving.

Spikes along the top of the fence and a big CCTV sticker.

Is there another neighbour that could keep an eye out too? That is really weird and intrusive behaviour.

Both civil and criminal trespass involve entering an owner’s land or accessing the owner’s property without permission. Criminal trespass involves entering or remaining in a place knowing one is there without a license or privilege

If she felt intimidated then the police would be interested. Is he displaying stalker behaviour?

I would wait and see if it happens again.

If you ask him now there’ll be something innocent like ‘oh I saw you’d gone out and I heard a burglary type noise next door so thought I’d best check it out’.

If your friend catches him multiple times it’s...it’s creepy and harassing.

Incidentally did he try any of the doors to the property to get in?

They need to move. Nothing good can come from this situation.

Put movement sensitive sprinklers all over the back garden

Perhaps your friend could ask him if he noticed anyone in the garden while they were away, as it appears that some things have been moved?
It keeps it innocent, kind of, IYSWIM? If he hasn't noticed the CCTV, he doesn't need to be alerted to it. Just see what the reaction is, and in the meantime, keep recording and keep a record (manual) of anything untoward. Don't know if this is a useful suggestion, but hope so. However, if your friend lives alone, or is a single parent, I would be inclined to ask for some advice from the local constabulary. I have found them to be extremely helpful. Good luck to your friend!

cornforthwhite moving would be a bit drastic.
I personally would let him know he was recorded and ask why he was on the property .
Also good to use the stickers letting one know they are being recorded.
Quite concerning but at least your aware.

Well this is disturbing. No, there can't be an innocent explanation.

Leave an old key from an old unused lock under a mat or plant pot. See if he tries it in a door. Then you will really see what his intentions are.

I don't think there is such a thing a criminal trespass in English law.

Don't tell the neighbour there's a camera. He might disarm (if that's the right word) it and break in.

Did he know the friends would be away?
Just thinking as it is unusual for people to be away at the moment he might have been checking everyone was ok if no movement from the house?