Thanks for the advice ladies - much appreciated!
These seem like the perfect nappy for me - the fact they're bulky on a newborn isn't an issue for me, as I have a set of newborn fitteds (I just can't resist cute fluffy newborn nappies!).
I have just bought one Greenkids nappy which I've got on really well with (so far anyway!). I've tried lots of different pocket nappies and they all have their advantages and disadvantages. Although aplix is a pain as it's easy opening, I do find it easier to get a better fit with it - and if my son is trying to open his nappy I just put some tight trousers on over the top and distract him with a toy which usually works! I quite like the bumgenius but I have found they are a pain to wash, and they started looking tatty very quickly.
The cost of a greenkids nappy + insert is actually less than I thought - and only a little more than a bumgenius, which I was initially planning on buying a set of anyway.
I will buy the Greenkids inserts (second hand if they come up - I agree with you about the patience thing, i havent really got the patience for prewashing!) and then buy some cheaper boosters and microfibre cloths. I've just bought a few packs of 5 Easy Peasy hemp boosters which are great and I'm sure they'll work with a GK insert.
Thanks again ladies