The plugs were changed at the service but I then had a misfire problem in low revs. Took the car back to see if one of the new plugs were faulty but have come back with leads and 2 coils to be replaced.Welcome to the forums
Just out of interest, how do you know the coils need replacing.
Leads are really an easy job to do yourself and cost about £30 per pair.
Cost of coils, I don't know but still quite an easy job.
Probably a 1 hour job at a garage. Maybe your plugs need changing at the same time.