On Tuesday, 16 October 2012 11:44:34 UTC+1, fred wrote:
We have about 10 lights using these GU10 bulbs.

The knobbly surface of 60 LEDs gives plenty of grip, and you don't need to change them often.

If you haven't yet got 60 LEDs in your GU10s, then replace them. Maybe use an angle grinder to get the old ones out.