Can't Lock Device post flash to new ROMs

[T39andcounting]

I've recently flashed my Orange UK diamond from the original Orange ROM to a cooked ROM, and since the update I've been unable to Lock Device... a long end key press makes the screen flash and return to the Touch Flo home page, but the device remains on, without keys locked. If I change the Long Press End Key option to display Quick List, then tap Lock Device the same thing happens. I've seen a couple of posts with the same issue, but no resolution.

My upgrade path was as follows:
Original Orange UK stock ROM
Unsigned-Hard-SPL-Diamond-OliNex
Diamond_Radio_1.00.25.05
SwiftBL-WWE-Diamond-ROM-v6.2-Full
Duttys_Diamond_5.2.20748_V1_9_Radio_1.00.25.07_Ful l
SwiftBL-WWE-Diamond-v6-5-Full-16MbPP

I tried Key Lock on the last 3 ROMs none of them worked (one of the reasons I tried the other two ROMS after 1st flash). I didn't try key lock after the Hard-SPL flash, so maybe an issue with Hard-SPL?

Does anyone else have this problem? Anyone got any suggestions on what might be the problem? Any other information I could supply to make this easier to diagnose?

Sorry if I've posted this incorrectly, but I'm a newbie to these forums!

[iXiR]

Cooks can change settings. Maybe the set locking off. Download advance config and enable locking. It can be found here: http://www.touchxperience.com/en/advanced-configuration-tool.html. Look under section "screen".

[T39andcounting]

I've had a look at the Advanced Config program. I enabled the "Auto Device Lock" option. This password locks the device when it's turned off for more than 5 seconds, but I only really wanted the key lock option (where a password is not required). Any other ideas?