[cheshired5]

There was a garage mentioned on here a few years back in the Accrington area that a few members used for core plug replacements which effectively needs a similar process.
They were incredibly reasonably priced for the labour which I think was on account of them doing the job many times and lower overheads. £350ish from memory versus £700-800 labour in a dealer.

I'll rack my brains and see if I can find the threads unless anyone else remembers them.