I now have to drive due to medical reasons so thought I'd offer to drive others in via the Let's Carpool website but I don't know what to ask for, has anyone got any suggestions?
I'll be driving all the time and using my own car.
alasta: I'm pretty sure that Inland Revenue publish guidelines for per-kilometre reimbursements of private vehicle use for employees. That would give you a pretty good idea of what to charge for the distance that you're travelling.
If you can't get anything from Inland Revenue then the local chamber of commerce should also have this information.
Figures that you get from either of these sources will give you a representation of the total operating costs for your vehicle. Don't fall into the trap of just charging for petrol because there's a lot more cost in tyres, servicing, brake wear, etc.