upgrade to CID52 with setool2lite and use the following files to flash your phone
MAIN : K610_R1KG001_MAIN_GENERIC_TH_RED52
FS : K610_R1KG001_FS_EUROPE_1_RED52
custpack : HB1-06_Generic_CDA102568_10_R4A_GENERIC_EUROPE_1
you'll get these files in the download area
and read here for flashing and unlocking : Flash your phone and How to apply or remove patch using SETool 2 Lite - Top Sony Forums