DHD Return Stock UK topic

I've not used my DHD in a long time. I think it was unbranded when I brought it from Phones4U.
It currently has CM10 or CM11 on it and I want to revert it to pure stock.
I've run getvar and this is the info...

Bootloader: 0.85.0024
Baseband: 26.17.14.11_M
cpld: None
Microp: 0438
Main: 1.32.405.3
Serial: ***
Imei: ***
Product: Ace
Platform: HBOOT-7230
Modelid: PD9810000
Cidnum: 11111111
S-Off

I understand an RUU is the easiest way but I also need to S-On first.
Can some knowledgeable please direct me to correct tools / RUU for my purpose.

TIA