Urinating upstairs

[QuickstepQueen]

We've had him from a pup - toilet training not really needed, he just didn't do it. Around 18 months started allowing him upstairs - well he finally wore us down...and then he started to wee upstairs only - we sought advice and got his bits chopped off and put him on a lead for 6 weeks and everything was fine.
He's now 5 years old and about a month ago I noticed a couple of yellow marks in the guest room - not sure when this happened, I don't go in there often, but I had my suspicions that he had wee'd!

Then last Tuesday he did a wee in there and I caught him - nothing happened beforehand that would have upset him - I was downstairs and there to let him out if needed but he didn't ask. Then later dc tells me dog might have wee'd in his bedroom.

So we decide to not allow him upstairs anymore - upsetting because he normally sleeps in our bed - we miss him and he clearly wants to join us. (Have checked with the vet and she thinks it's behavioural rather than a UTI and encouraged us to consider what might have upset him - nothing we could think of).

So how long do you think we need to ban him from upstairs - any other advice?

No idea really but I wonder if it's the fact that it's a relatively new environment.

Whenever I take BiteyDog into a new place like a new house I always deliberately take him outside frequently like he was still a puppy and give him the command to pee and praise him so he knows outside is still the place to go and not the new rooms.

Make sure you clean up the areas he has peed in and supervise lots until you are sure he isn't toileting upstairs.

I wonder if it's the fact that it's a relatively new environment. It's not a new environment though - he's had access to the guest room for 3 years without an incident. He occasionally sleeps there during the day.

Have you cleaned the area with an enzyme cleaner?
If not it could be that Ddog can smell where he has urinated before so is repeating?

Use simple solution to clean the accident spots properly to make sure he doesn't just keep marking the same areas over and over.