Blown Head Gasket

Hi all. I have a Renault Clio 1.4 Mk3 2007 and after the car failed to start I took it to the local garage and they have told me its a blown head gasket. It failed a coolant hydrocarbon test . They have estimated the cost of repair to be £1200 which includes 11 hours labour, skimming, water pump, cam belt kit etc. This estimate seems quite excessive.



1) Could there be any other reason for the coolant to fail a hydrocarbon test?



2) Is the repair estimate reasonable?



Thanks