Well the garage told me it was the core plugs in the cylinder head were
leaking, I am wondering why they failed, if indeed they had failed, I wish
I had my own workshop, I do not trust garages at all.

I asked them to keep the old parts and when I turned up after they kept
the car for a day and a frickin' half they said oh no sorry we threw them
away.

Sounds like a pro con-trick to me, dispose of the evidence.

This is a main ford dealer as well.