I will give Chris a call in the morning and prompt him to check his email and/or his spam folder (and Facebook thing).
The airplanes available here are on the Coconut Airways website booking page.
N666BK - the rates are sensitive to fuel costs assuming that the current B$14.5 to 16/USG remains good.
The rates are certainly lower than the UK (and the weather tends not to get in the way!) - the Tomahawk goes for, I believe, B$280/hr, the Arrow for B$400-450 (not sure of precise rate) - both of these are Barbados registered. The Archer II, US registered (I must declare an interest as it is my airplane) goes for B$400/hr - some flexibility on a block of hours and low daily minimum for fly away if you want to do trips to other islands.
Executive Air also have a US registered Archer that they operate for an owner based on Union Island but is mainly in Barbados.
Do be aware that to solo a US airplane here you will need an FAA licence (getting a piggy-back FAA issued on the basis of a JAR licence is a good idea) - to meet the "two out of three rule" US airplane, US licence and airspace. So you will probably want to rent one of the Archers as they are US registered if you have plans for day trips to other islands and do not want to go to the trouble of getting a Barbados licence issued (things here can take quite a while) - if you just want to fly around the island any ICAO would let you solo a Barbados airplane in Barbados airspace.