I'm not sure if they only do Olympus, but they can do warranty repair, they're so nice to deal with and soooo quick.
I bought a 12-60 on ebay a week or so ago and promptly flung it across the road, breaking off the front of the lens.
I sent it to Luton Camera Repair services last Tuesday and they:
Dismantled lens unit, supplied and fitted new iz frame, cleaned and polished iris blades, cleaned and reset castings, rebuilt aperture control mechanism, cleaned and refitted elements, refitted helical, reset stops and adjusted focus.
This cost . . . . . £83.70 excluding VAT
The lens was back this morning, apparently operating flawlessly.
Hooray - and thank you to them.
all the best