H means "high sensitivity". Which means Garmin used a newer GPS chip with
better sensitivity. IMHO a huge improvement over the "non-H" series;
especially under wet trees etc.
>
> - Whether accessories bought for the H and non-H series are
> compatible? (Cycle mount, Neoprene case, Serial cable etc)
Sorry, Dunno (I've got a 60CSx and Legend HCx)
>
> - Which one should I choose to buy for a GPS newby probably
> mostly used for mountain biking with a bit of hiking?
IMHO certainly a "H-version", preferably with (topo-) map. I use a Legend
HCx on my MTB.
>
> I notice the "old" pre-H model is more expensive in the UK
> than the H series equivalent!
Weird.....Etrex H is 85-95 Euro here in Holland
YMMV, FF