Cheers for the input, I'll look into the options 🙂
The wearlink straps sound much better than the old plastic ones.
I'm not too worried about GPS I guess, the distance/speed/HR calculations which will work on the MTB bike and when I run (very rarely) are really what I am looking for. I'm not planning on having any kind of major training plan, but no doubt it'll be useful as a guide to keep me in a good place and to give me a bit of a kick up the arse! I used to use my old polar one a lot and found it great, even for the simple stuff like keeping an eye on resting heart rates.
I've heard mixed reviews about the Garmins…with the 305 being great, but the 405 being a bit of a disaster unless you don't want to fiddle with it when it rains.