Chris
We went to Guernsey around 2005,I think having been to Jersey 2 yrs on the trot before that & France all the years before-mainly because we had never been there at all.
All occasions we rented accommodation & took my windsurfing gear .On Guernsey our holiday was deliberately timed too accord with the Guernsey Flower Festival & we stayed at a place called Mille Fleurs which had a 7 acre landscaped garden & featured in the list of gardens open for visits during the Festival-in fact there was a garden walk round with Mike Nelhams ,the Curator of the Abbey Gardens on Tresco where we had been 2 years previous.
It's a beautiful island-quite narrow lanes ,low speed limit (20mph IIRC),no overtaking but being small,it doesn't take that long to drive around it.
A lot of interesting places centred on St Peters Port & environs including:-
Castle Cornet,German Occupation Museum,La Vallette Underground Military Museum ( also a hospital but seasonal),various Nurseries -we went to the north Island St Sampsons one where they mass produce Freesias in rotating order using long plastic enclosures- you can buy flowers & corms.
Then there's Sausmarez Manor with subtropical gardens,a dolls house collection etc.
I have got the Guernsey Visitor Guide here but I bet they'll mail it to you-enquiries@tourism.guernsey.net--01481 723552