I've just been told I have a leak in my head gasket (Outlander '07, 46,000 miles, just out of warranty). Does anyone know if this is normal or has it happened to them ?

I'm concerned as I would expect something like this to go around 80-100 or later, but not after 3 years of town driving. Mitsubishi are telling me it will be £1,000+ to fix, and would like a second opinion before proceeding. Does anyone know if I can take this matter further or am I stuck bearing in mind I am out of warranty.