Graham, I was so excited to get the email notification that you had posted, and so glad that you are doing well with your two year old hip. Mine will be two in a few days, and I've not had a moment's trouble with it.
Bicycling is great, and thefts and storage can sure be discouraging. But there you are in the UK, where Brompton folding bikes are made. I received mine a month ago, made to order and all the way from England to Florida, and oh how I love it. No storage problem with a Brompton.
I needed a folding bike because I live in a second floor condo, and carrying my bike rack and bike downstairs to load onto my car is okay, if I'm going camping or going to take a long ride, but mostly I just want to ride for an hour or so and I was finding that I seldom rode any more because it was too much trouble.
Now my adorable little Brompton (I promise I am not on their payroll) is stashed behind the passenger seat it in my car, and I can whip it out and unfold it and put on my helmet and be riding down the bike path in less than a minute of arriving at the trailhead. I've been riding almost every day that I don't go paddling early.
A folding bike might be a great solution for you, too.