Thanks everyone. This has been really heartening - lots to think about. To answer a couple of points upthread:
Get a cat - yes! Last time we went through this thought process we drafted a list of exactly what we needed from a breed and came to the same conclusion. Don't regret that decision at all, our cat is our leader. Things have changed a bit for us though, ten years on and we're in our early 50s, we're outdoors a lot more and have more time on our hands.
Training - totally agree. Where we live there are so many dogs, the majority of whom are poorly trained. We're fully prepared to put serious time into this - we've both grown up with dogs, me from puppies and DH all rescues, so we understand the importance of getting the right breed then putting the work in.
Walks - I think I undersold our position probably. We live on the edge of a massive park with woodland perfect for off-lead romping. I walk there every day myself, so adding in a bit more time and doing it twice a day is no problem. I'm more concerned with finding a breed that's happy with a couple of daily romps PLUS can handle the odd 10miler at weekends. I met a fell runner a few years ago who had a toy dog - he said it was perfect, they'd just chuck him in rucksack when he got tired. Maybe this is a thing?
Labs - love them and seriously considered a pup about 5 years ago, which is where we heard about being careful with their hips. I didn't realise that applied to all other breeds though... I don't know anyone who's followed that rule. Poor pups :(
Breeds - gah! I love all these suggestions. Greyhounds are gorgous (if a little snoozy, but maybe that's right for us) and the schnausers and show cockers are where we landed last time. Having met a lovely staffy recently, I'd consider one of those as a rescue too. I quite like the idea of having a different sort of dog - we're in an well to do area with mostly labs, viszlers and cockerpoos... I think phoning round rescues is a great idea, we'll try that before investigating breeders.
Thanks again all of you for taking the time to reply - if we go for it next year I'll post a picture and you can see what we went for!