I've broken a long reader question into component parts.
Issue: I'd been having lessons with my coach for about two years, but I wasn't too happy with them. I love her as a person, but she'd often be talking to the other coaches or texting when she was supposed to be watching me.
Problem: unprofessional coach, disengaged parents, student unwilling to demand her rights
Solution: read that coach the riot act, then fire her
Issue: we would spend so long working on the field moves for exams that we had little time (in the one half-hour lesson I could afford a week) to work on spins and jumps, and I felt that these suffered as a result, as all our focus was on the field moves for my exam.
Problem: conflicting goals, not enough time, poor communication
Solution: make your goals absolutely clear, and make sure you understand, and that the coach conveys, what it will take to reach them. I'm stunned at a student taking just a single half hour lesson a week being told that Moves tests take priority. It's absurd. Moves is ADDITIONAL, not the only thing you work on.
Issue: I went off to university, with our understanding being that I would continue to have lessons with her in the holidays;
Solution: You hate the coaching style, she doesn't share your goals, or indeed pay attention to you during lessons, and basically wastes your time. Going away to college was a gift-wrapped excuse to move on without hurting anyone's feelings.
Issue: after a year of missing out on skating due to being at uni I'm faced with a 3 month summer holiday where I'd really like to get back into skating, and this obviously must include lessons, otherwise I'll never improve. However, I don't think I want to go back to my coach, for the reasons above - I want to just be a recreational skater, trying things for fun, whereas she'll want to push me towards grading, which I have no interest in.
Problem: see previous issue. You have no obligation to this coach. You haven't taken a lesson in a year, and didn't like the lessons. No reasonable person would expect you to continue this relationship, and nothing in PSA ethics or even simple courtesy obligates you.
Issue: she still coaches my sister it's an awkward situation,
Problem: creating issues where there are none. Many families have different coaches for siblings, to make sure that the coaching style matches the student, to avoid rivalry and comparisons, to accommodate schedules and a host of other reasons, or for no reason at all. There's nothing in any coaching manual that says a family can only hire one coach.
Solution: First, the parents need to observe these lessons and make sure that the coach is not pulling the same crap on the sister as on my reader. I cannot imagine why this family feels so committed to this coach.
Issue: I cannot swap to another rink
Problem-- Need more info here. Is there NOT another rink? Transportation issues? I hear this a lot, and sometimes it's more "I'm afraid to switch to another rink where I don't know anyone"
Solution: make sure this is really true before you rule it out.
Issue: I don't think that any of the other coaches will have space to take me on, and most of them at the rink seem to, shall we say, have a similar coaching style to mine.
Problem: Your rink is a mess.
Solution: Run away and don't look back. No, seriously. Observe some of the other coaches. Look for coaches whose students seem to have similar goals and levels to your own. Tell the new coach in so many words exactly what your issue was with the old coach. The old coach is NOT your coach anymore; neither you, your sister, nor any coach you speak with is under any obligation to report that you are making inquiries.