Thanks for the replies, it's my first garmin too. From what I can tell David, it is a reduced spec version of the 800 for less than half the price
You don't get cadence or heart rate, which I'm fine with and the mapping is less detailed than the
ordnance survey mapping on the 800, but I was advised that once you have zoomed in enough to benefit from the more detailed mapping, everything goes past too quick so you have to zoom out taking away the advantage of the extra detail ( this is only what I ave even advised not my opinion as I haven't ad the chance to compare)
I will try the garmin forum (thanks Ian) and after that will try as medic suggested and select the 800, many thanks