Luckily we have shed loads of baggage allowance so can take my bike stuff if need be.
Is there anywhere that rents decent bikes and can show me where to ride?

No.

Best to take a road bike and thrash yourself in the heat, Barbados is fairly flat. You could catch the shuttle over to St Lucia where the is “Tinkers Trail”, but its not the mecca you’d be used to in the UK.

<holiday willy waving> 😉

I’m taking my bike to Verbier, plenty space in luggage for my speedo’s, any good beaches?

given the size of some of the sink pot holes in the roads i wouldn’t fancy the road bike either

There’s the odd bit of singletrack on the east coast but the whole Island is pretty flat and moderately heavily developed.

…and its only very small, you’d ride round it in the morning.

I shall stick to the wet bits then.

When I fly to Barbados I take my road bike. It’s certainly not completely flat, with some pretty large hills. I seem to remember having googled mtb riding there before, and there is a bit, but not a lot.

I wouldn’t go wandering in St Lucia – a few of our pilots have been mugged from their bikes by machete wielding gangs.

There’s not a lot of it, but there are some good offroad routes through the sugar cane. If you’re on Facebook check out https://www.facebook.com/MountainBikeBarbados