Thanks very much for all the replies. You've put my mind at ease, I'll give it a go. I've got 350gr Barnes TSX at the moment, I don't suppose they will open up too fast on a small deer.
To answer a couple of things that came up - getting deer stalking with the rifle was no bother. The land owners I shoot deer for have known me for a long time. They're not bothered what I use, they know I'll shoot safely so I can do as I please. Some of them find it rather entertaining just trying to guess what I'll turn up with next! The police were a little reluctant to allow it at first but I have a lot of good references to back me up.
Bullet pass through, pretty much all shooting is done with that in mind here. We're so densely populated that the use of any centrefire rifle has to be quite carefully weighed up. Some of the ground I shoot is very steep so there is always a good hill behind my intended target. It's all about the backstop and I'm lucky to live in an area known for it's hills. It's actually called the five valleys!