Hello Ironass! Thankyou for your welcome and reply
I do indeed have the o2 Branded Galaxy S2 NFC (i9100P)
The firmware installed was updated last week via Samsung Kies.
Very confusing to see that it's actually another carriers firmware?
I do not have the original full kernal unfortunately. I didn't know how to back this up, or if it was indeed possible. So I just rooted the phone with CF-Root-SGS2_XX_OXA_LPH-v5.2-CWM5
After three more attempts with the same LPH Kernal this morning I tried using CF-Root-SGS2_XW_O2U_LP3-v5.4-CWM5 which seems to work ok!
The parts o2u and LP3 seemed similar to the CSC i9100Po2ULP4 which is listed in my phones version.
Have I done the correct thing? Many thanks.