Your wife wouldn't be sitting at home all day, that's for sure – there's loads of stuff to see and do – whether she's into shopping, more shopping, eating or maybe she's outdoors-ey and prefers hiking, sailing?
It's a lonely place if you don't know anyone though – my mum worked as a school nurse to stave off boredom – also meant that she met a lot of expat mums and dads. Appreciate your wife might not want to do this, but I'm sure there are plenty of other expat social networks (perhaps she likes horse racing? 🙂 )
I've always found living space to not be that much of a big deal really. However, on a return visit recently, I appreciated just how noisy the place is. 8 floors up at 3am and I could still hear a steady stream of traffic below. Obviously there are quiet areas too, just need to work a bit harder to find them.
unless your dog is v. small or you plan on living on one of the outer islands, I suggest you might consider leaving it in the UK 🙁