Ford Focus, gone from a split matrix heater hose to a headgasket?

My daughter's car broke down on the motorway after losing power and smoke from under the hood. It was recovered and we were told there was a split matrix heater hose. Got this repaired for £60 inc part but the car is still not right. Rev counter not correct and car feels like its going to stall. Got guy to have a look again and he has told us its the head gasket. Its a 54 plate with about 70k on the clock. What do you think? :-(