Gnomeland is one relatively small part of Watermouth Castle which prides itself on being the West Country’s premier attraction. It is difficult to say what it is really, part museum, part theme park, part automaton collection with a pretty good dancing water show and more. If all you are after is gnomes then you would be hard pushed to justify the fifteen quid entry fee. For most of a family day out (I think after 3 or 4 hours you would have seen and done everything there) it might be worth a look but check it is open first, they seem to be closed on Mondays and Fridays at the height of the season.
Gnomeland itself is probably eight or so automatons, some single gnomes such as the grumpy old gnome who welcomes you to Gnomeland (Apparently his wife is on a diet and is trying to lose three ounces). Most are gnome houses, where you can see gnome potter potting, cooks cooking, babies waving etc.
There is also a gold (which they call gnold)panning place there and when you have collected 4 pieces of ‘gnold’ you put them in the shoot of the gnold minting machine along with two 10p coins and you get a gnome coin back. I rather suspect that you could get your coin by just putting 20p in there but that would not be entering into the spirit of things would it?