House move issues

[Montalf]

I moved into a first floor flat 2 days ago and today received a note through the door about my dogs 'constant' howling and barking and if it doesn't stop I'll be reported to the council.
I know they have howled twice when I have left them, once yesterday and once today, however I was out for around an hour each time and they were quiet when I returned in fact they were so knackered from the walk that they didn't even notice I'd come in they were that fast asleep! I have issues with the wording and tone of the note, however right now I need advice on how to stop it.
I have to go places without them and I know they're unsettled right now but the neighbours are unsympathetic, despite having their own dog (that I actually heard on first day here while they were out!).
I've put a radio where they will be, one is in a crate (6yo jack Russell) the other has bed in small porch area (9yo westie) they have water, toy each and are left with a treat, its warm and there's no windows for them to see outside (bottom of stairs to main flat) they have howled on odd occasions before and it is for 10/15 mins max, I don't go back in because all that is teaching them is howling gets attention.
I need to stop this asap - help!

They are obviously upset about the change to their environment, how do you know in 2 days that they have howled?
Your dogs will settle, the neighbours will probably complain if you still farting in 6 months and they can 'hear you' just give the dogs a lot of fuss and rassurance they will get used to the new surroundings and that you will come home

I heard them as I left, however I don't believe going back in the answer because that's just going to teach them if they howl I go back, also don't want them howling every time I leave and this becoming a habit! I have explained to the neighbours about moving and being unsettled etc but they're not interested. Can understand it's frustrating for them but there's not a lot I can do that I'm not already and to be fair it's not hours and hours every day and we've only been here 3 days now

Could you speak to your neighbours and find a time they aren't in. Then perhaps you could leave during this time and only go back in and reward their behaviour when they are quiet so you are building up there confidence that you will return but doing it at a time when the neighbours cannot hear.

I have read moving home can cause separation issues so it isn't surprising they are abit upset at the moment. Do you know if they cried when you left before you moved?

Could you move them to a different part of the flat to minimise noise for the neighbours? Put them together to see if that makes a difference?

I have moved them to a different place in the flat to try and minimise noise as suggested (many thanks) leave them with chews and a portable DVD player on and the washing machine on when I go out, I've tried to stagger leaving them from starting with an hour, however I have to work and that can be 4-7 hours. They're walked and fed and all the usuals and are in the same room, however they need to be separated (one in a crate) especially with chews about, as they have been known to scrap over chews and so I don't leave them unsupervised together.
The jack Russell I've had from a pup and is well trained (sit, stay, recall, speak, quiet, leave etc) the westie is older and putting it bluntly an ignorant little sod! I got her from someone who needed to rehome a few years ago and although she has improved a lot since I've had her there seems to be some truth about old dogs and new tricks!
Just trying my hardest to help them feel secure, not upset the neighbours and earn a living!