Welcome, Lesser!
To answer your questions:
My problems are that I don't have much time to cook (I get home about 7pm on a good day) and I have vegetarian tendencies and really can't bring myself to eat fatty meat. I've also read that nuts are too carby and may stall ketosis, and so might dairy...so what does that leave?
Planning ahead is really important with low carbing, to make sure that you have the right foods to hand. Meal plan, and then make sure when you're doing your shopping you get everything you need for good low carb meals. It's harder to low carb if you're a veggie, but not impossible. Have a look at the Bootcamp recipe thread for some inspiration - lots of lovely veggie stuff there.
It's REALLY important that you eat plenty of fat; you may find that as you get used to low carbing, your tastes change, and you enjoy it more. Try and avoid really lean cuts of meat if you can - or if you can't, then have them with a creamy sauce.
Also I'm not in the UK so some of the foods you all suggest are not available: every single tub of yogurt in my local supermarket is either lowfat or no fat, I checked them all.
Can you buy cream? Double cream (or heavy cream if you're in the US) added to yoghurt would be a good solution
Ideally I'd like to weigh 9st but have also read that it's easier to lose more and gets harder when you have relatively little weight to get rid of. Is that likely to apply to me? (Am also ancient and get no exercise atm.)
It's true, weight loss will slow as you reach your target. Don't worry about either your age or the lack of exercise - it's diet that's the most important thing (And I"m probably more ancient than you at 54!)^
Should I do ubercamp (frightened to check exactly what that involves) or will I still make progress with regular bootcamp?
Ubercamp is a really low carb, no-dairy plan, that lasts for three days. There's no need to do this, unless - after having Bootcamped for a while - you believe that you have a dairy problem
Hope that helps!