Can you recommend a good iPhone4 repair centre (postal)?

[megandraper]

My iPhone4 has developed a fault with telephone calls - no-one can hear me, though I can hear them. It is also often dropping calls/failing to put the call through.

I need to send it for a repair (out of warranty and a long way off the upgrade date on my contract).

Can anyone recommend a reliable repair centre - I will send it by post, most probably.

Thank you.

Have you checked that it's nothing to do with the 'grip of death' issue? iPhone 4 is notorious for its poor phone call ability.

ha! to grip of death - i have done that in the past.

No, I think it's more than that. I was looking at the Fix My Iphone and the repairs 4 u sites, and am thinking of using one of them.