Moving from house with garden to a flat with 8 year old barker

[GoingDownLikeBHS]

We've lived here all his life. Last few years have been difficult due to illness and divorce, so we haven't focused on dog behaviour and now I am worried as he normally sits on the back of the sofa in our large picture window going apeshit at foxes, cats and delivery men. There's no sofa for him to look out the window at the new place - I'm wondering if this will make him even worse. His routine will be changed as well and I am thinking he's going to be very down.

He also normally barks when he's lost a toy under the sofa, barks when he knows its treat time, barks when I get his lead out. In a large-ish house it's not been an issue, but in a flat how will this work out? I know some people think a dog should not even utter a woof once a day, but where we live now there are a dozen dogs sitting on sofas at the window sills going mad at the postman, no one cares.

At least we are ground floor but how on earth will we calm him down?

I moved with a barky dog from a first floor flat with a vantage point - he would bark at postman, other dogs etc, to a house with nowhere for him to look out and it improved massively. Now his only triggers are when he's outside and hears other dogs barking. For when we're in the pub or a no-barks situation, I carry 'bark spray' the can of compressed air which makes a noise dogs don't like. I've had the same can for several years as now the sight of the can alone means he gets the message.