Fellow brit here, living in St Kitts for 15yrs.
You are going to love our island. We have so much history and great local people
You are visiting ports with better beaches (not that ours are bad, but others are better) so I would stay land based and enjoy the island.
You will appreciate that this is very much a "no hassle" type of place, our vendors want your business, yes but not to the level of almost aggressive bullying you can find elsewhere.
For island information that is bias free try this site St kitts tourist information .
For tours and local journeys we have many good family companies Like this one.
Above all relax and enjoy, in St Kitts we " rush slowly"
Carib is the local beer, comes in Pilsner (light), regular and "Blue", Blue is falling down water 8% proof.