Apologies, I didn't check the thread over the weekend.
Thank you all so much for your replies which are really reassuring to read. I really like your suggestion to go and try another airfield and instructor and see how I get on. There's one nearby but they are on the same CTAF so I might have to put an accent on : )
I must admit I haven't had much experience flying GA when I haven't been doing the flying myself! It's all been somebody teaching me and now it's just me on my lonesome up there. Spending some time with an experienced GA pilot and just watching them fly would be really beneficial for me.
I do wonder if with the first more dangerous incident in my career, some things were brushed under the carpet that I wasn't aware of. I got a roasting at the time by the CFI and with only 15 hours I didn't feel I had much room to argue with what they were saying. It's only with hindsight that I realise that things might have been missed in my training. The next lesson I had was certainly focused on go-arounds! My main instructor left shortly after that incident and after that I had a rather varied succession of instructors which probably didn't help maintain the structure either. Sometimes the personal touch can be very helpful.
Thanks again.