Right, sorry for dragging this out!
I can get a Forerunner 10 for £75 or a Forerunner 110 for £80.
The main differences appear to be that the 10 looks better to me (in orange!) and is fully waterproofed and battery lasts 5 hours, but the 110 looks more like a normal watch in grey, is not fully waterproofed and the battery lasts 8 hours.
Realistically, I should probably get the 110 due to battery life and the fact that I don’t need it for swimming, but I’m finding the orange 10 quite alluring for some reason.
Are there are obvious differences I should know about? I’m going to buy one tonight.
Another difference is that the 110 can be used with a heart rate monitor, but I’m not really bothered about that.