Being honest, while I’m a big Islabike fan, we didn’t bother getting our first until the Beinn 20 small – the smallest bike they do with gears. We never really did any distance riding with them until they got gears (I think a few miles was the most we ever managed) so I never bothered to spend the money, just picking up pig iron, eBay specials for next to nothing for their first bikes. The heavier bikes didn’t seem to put them off and I suspect that your Cnoc will be way lighter than ours ever were.
Once we got the geared Beinns, suddenly we could cycle decent distances and the era of “family bike rides” started for us….and still goes on today, with the one difference that it’s now my wife who can’t keep up with the kids!