[Closed] Clutch problem, help needed!!

The clutch pedal on my Mercedes vito 112 51 plate dropped to the floor and wont return while I was changing gear the other day, it wont engage any gear etc and remains in neutral. I was thinking it was the master or slave cylinder. Is there a way of identifying the fault? What sort of cost/man hours would be involved? The van has done 101,000K and is well looked after and not abused. I Phoned a garage and they said it was probably the slave cylinder and the gear box would need to come off!! Is this correct? Any help much appreciated thanks!