Cylinder Head Gasket

My car is just shy of 50,000 miles, and is starting to overheat slightly - we've done a compression test, and it looks like the cylinder head gasket needs replaced.

My mechanic (who builds racecars at the ring) is advising me to replace the rocker arms at the same time, as they will need done soon so worth doing at the same time.

Anyone else had any similar problems to this? Admittedly my CSL doesn't live the easiest of lives