I'd just like to say a big thank you to everyone who replied to my last post. Your words of encouragement have helped me so much, as this latest rejection really bothered me. I think the worst thing about it is that the feedback I received has made me doubt my own work. I was feeling really confident about the novel before and believed it was ready to go, but now, not so much!
It's not that I can't see what this agent is saying - I can and I'm very open to feedback and to making changes. But in this case, the changes involved would alter the novel a lot, so I'd have to be sure I'm doing the right thing before going ahead with them. If I get the same feedback from other agents, then I'll get to work on those changes, but I can't risk ruining what's good about the novel at this stage.
Every time I have doubts, I'm trying to remind myself that this is just one person's opinion and other agents will (and already have) have different likes and dislikes about the manuscript. And I can't keep them all happy - that would be a lot of rewrites!
But having said all this, I would recommend Sarah LaPolla to anyone thinking of querying her. She clearly took her time reading my work and provided me with detailed feedback, which she didn't have to do. And when I emailed her back to explain some of my choices for the novel, she replied again with further thoughts on the work and more fully explained some of the points she'd already made, which was really helpful. For anyone lucky enough to have her as an agent, I'm sure she's wonderful to work with!