Hi all, I wanted to add that my daughter cluster fed every evening till she was about 16 weeks and still now at 23 weeks she has three feeds in very close succession in the evenings before she goes to sleep.
I was tremendously grateful for mumsnet (and for kellymom.com) for reassuring me that this was normal as, like you Sophie, I didn't even recognise it at first and thought she couldn't possibly be hungry AGAIN. I am also very grateful that I didn't take any notice of anyone/any book that suggested she should be in some kind of regular routine - in return for the two or three hours of cluster feeding every evening, she started sleeping through very early, and has always been a great night sleeper.
For what it's worth - she found herself a settled pattern in due course, her bedtimes gradually got earlier, and we have coped with a couple of growth spurts as well, so you may well find that the cluster feeding stops for you too and that the routine becomes predictable all by itself.
I am so glad that I just followed her lead on everything and never worried about waking to feed, frequency of feeds etc. As it turns out she knew EXACTLY what she needed - I think it's worth trusting your baby as much as you can.
Good luck, stick with it, it gets easier, and you are doing the very best for your babies.