Depends on condition of drive, FSC or variable fan jet we have done a few
if the drive is ok do a demo using FSC (seen loads that are pants and know of few locally that have been ripped up and replaced with tarmac or blocks - seem to fail if the drive has tight turning circles stones get ripped up it there isnt enough resin) gives you a good indication plus shows customer you know what your doing / shows end result ,start with low pressure slowly build up as drive warrants . Little tip start the FSC on a piece of board protects the stone from initial start up as this can rip the drive.
I would price for clean plus fungicidal wash, plus option to seal one or two coats this year, allow yourself 4hrs coating time /day.
Chris will be along shortly
and he run's the best cleaning company in the UK !
(well Merseyside) .... occasionally he escapes and jumps over the fence