IOS 6.1.1 and 6.1.2-no service on EE

Anyone else experienced this same problem?  I upgraded my 4S from IOS 6.1 to 6.1.1 a few days ago and immediately lost all celluar access on Orange EE - nothing at all, no 3G, GPRS or EDGE, just says "Searching.." or "No Service".  I've tried restarting the phone, turning celluar data onoff, airplane mode and reseating the SIM.. but cannot get it to pickup cellular signal.  I've just also upgraded to IOS 6.1.2 and exactly the same problem.

I did both upgrades OTA, but should that matter?

Any ideas, short of booking either a full reset or a Genius appointment ?

Cheers