I have the 410 but not a heart monitor (yet). I love it - I haven't had any problems with the bezel, and in fact I find it really easy to use. It's similar to an ipod wheel, so nothing too complex. If you're planning on doing swimming, I wouldn't recommend the 410 as it's only waterproof for up to 30 minutes when fully submerged. I think the 610 can be used for swimming, but I doubt the 405 or 305 can be.
£144 for watch and heart monitor sounds like a really good price.