Thanks very much chaps - my only small regret is that I have a couple more straps on order which will possibly never get worn!
I usually avoid silicone, but this is top quality - doesn't attract lint and has good colour-density - and just £8.59. Lots of other colours, too.
Has smartwatch-style clip-on attachment though, which I know some people are wary of - I've had a few straps like this and never any problem.