Thanks for the comments.
Everyone I have spoke to all reckons it will be ok.
I suppose I am just paranoid because they are "special" tyres ie RF !
As soon as the tyre picked up the debris I immediately could tell and only drove the car 4 miles at no more than 30 mph to the tyre repair centre and at no time did the tyre look at all flat and no sensors sounded to warn of a flat.
It was well into the treaded area of the tyre and the side walls were totally unaffected.
Maybe it would have been easier if the tyre was a write off as I would have no choice than to get new one then
I guess the overall principle of repairing the puncture on the main tread area is no different to that of a none run flat and I've had plenty of those repaired in the past.