Thanks again everyone for the helpful and thoughtful responses. I actually think a change of club might be good for dealing with the boredom of circuits too - that might be what I need to just get that bit of improvement.
I'm inclined to think that my club haven't exactly been on top of my training, from what everyone's said here. Although I'm going to try out another instructor for a couple of lessons and see how I get on, it doesn't sound like they're doing what they should be doing. Seeing that I have to move anyway, it's probably good timing.
Out of interest, can anyone recommend any particular instructors around Nottingham / Derby? I was looking at Truman Aviation as a possibility (I want to keep flying low-wing so the fact that they have Pipers is helpful).
Also, when I do move clubs, do I just need my logbook stamped or should I be retrieving other paperwork from them as well? I think they have the form with the exams I've taken so far signed off, which I assume I'll need if I don't want to have to go back to them when it comes to applying for my licence.