Which generic firmware? W850i

Hi all,

I had a phone on Three(UK) which I had unlocked by three and which my GF is now using on Orange. I succesfully rebranded the phone from this.....

19:14:20| Baseband ID: 9900
19:14:20| Protocol Version: 3.1
19:14:20| Phone name detected!
19:14:20|
19:14:20| Profiling SEMC phone...
19:14:20| Platform: DB2020
19:14:20| OTP CID: 49
19:14:20| EROM CID: 52
19:14:20| EROM Color: Red
19:14:20| IMEI: 35240101xxxxxx
19:14:20| Phone ID: W850
19:14:20| Region: HUTCH_1
19:14:20| CDA: CDA102677/2 R5A
19:14:20| Firmware Version: R1EJ001
19:14:20| EROM: R3A016

to this, which is obviously Orange Uk firmware.....

17:26:29| Baseband ID: 9900
17:26:29| Protocol Version: 3.1
17:26:29| Phone name detected!
17:26:29|
17:26:29| Profiling SEMC phone...
17:26:29| Platform: DB2020
17:26:29| OTP CID: 49
17:26:29| EROM CID: 52
17:26:29| EROM Color: Red
17:26:29| IMEI: 35240101xxxxxx
17:26:29| Phone ID: W850
17:26:29| Region: ORANGE_GEN
17:26:29| CDA: CDA102677/36 R11A
17:26:29| Firmware Version: R1KG001
17:26:29| EROM: R3A016

What I really would like to do, though, is use generic firmware so there is no company branding in the phone at all and use it on the Orange Uk network.

Can anyone tell me which main firware to use, which fs file I should use and which CDA file I need to use?

Thanks :)