Tbh I can't help much. Sorry. I thought from the title this was a thread for good ideas generally.
While I'm here I might as well chip in with my good idea.
I want to release a high strength beer called 'Responsibly' onto the market. That way all the other beer companies will have to ask the public nicely to drink my beer on their adverts. Guiness and that will have all their clever ads going, drink Guinness it will make you into a big strong ruby type or a black and white super cool surfer type fella or even a snail racing South American. But at the end of the advert they'll have to go, but by the way, Guinness is not all it's cracked up to be so please drink 'Responsibly' (TM) Cracked it.
By Law mind.
Even the NHS and the Government will be promoting my beer on every anti alcohol drive. How's that for 'genius' Guinness? Ya mugs.
With me? Excellent. I thought so. I'm after some initial start up investment so PM for a great opportunity with your bank details and the 3 numbers on the back of your credit card.
As to your space saving malarkey, I reckon I'd board it up and plaster it so to the untrained eye it looks like a wall. Then I'd use it to house a secret pub. You'd need a password, think lockins or the prohibition speakeasy. Your man could call out to the Mrs 'I'm just off out to my adult education class in "How to treat your betterhalf in the way she deserves to be treated" Night love. Don't stay up.'
Then, he's through the secret door like Batman. Tiny knees up in serene blissful peace follows. Just an idea. You could make him a tiny bar billiards set so that's Christmas presents sorted for this year.
It's a win win.
He'll probably be having some of my Responsibly on tap if he's a discerning drinker and follows Government Advice.