Here's a source of useful information on runflats and repair advice regarding the different makes http://www.etyres.co.uk/run-flat-tyres/repairing-run-flat-tyres/
Runflats can definitely be safely repaired if not too near the sidewall. I've seen some repaired far too close the shoulder though. To say that they can't be repaired under any circumstances is just plain wrong, if indeed that's what was said.
I've got runflats on my e91, had 2 maybe 3 punctures in the past repaired no problems at all. As someone has already said, as long as it's not close to the sidewall, won't be a problem.
The tyre is still fully up, it's a small nail in the middle so I will get it fixed £19 have been quoted so will go with that I think. The tyre is like new do fix it I think is best. Thanks for your advice