Transfer CSA -> Kingston

We’ll be staying for the last part of our holiday at CSA. Unfortunately, Couples don’t provide components transfers back to Kingston.

They quoted 350 USD for a private transfer. Is that what most people do to get back to Kingston?

I know another option is the Knutsford Express but that would mean leaving at 8am, swapping coaches (I think) and then a good few hours hanging around Kingston for an 8pm flight.

Are there any other shared transfer/minibus options that I’m missing? I can’t seem to find many options for Kingston online.