You should flash :
K750_R1NA005_MAIN_EU_1_CL_RED36
K750_R1NA005_FS_EUROPE_3_RED36 and finalize with
K750i_CDA102337_11_R5A_Generic_EUROPE_3, using G-Flash. Then you can apply this patch:
Remove_SIM_lock_K750_R1NA005_EU_1.rar (unzipped) in order to unlock it.
Search for "GFlash - flasher for K750i/D750i/W800i/Z520i; CID36"