GReddy FAT timer help needed

My timer does the preset countdown without a problem, but doesn't seem to want to do the auto feature - I set it to 30 seconds, go for an "enthusiastic" drive, but when I stop it's still at 30 seconds.

Also, when I tried to have a play with the attack mode, the timer just appears to switch off as soon as I release the handbrake.

The speed (purple) wire was spliced into the yellow / green speed wire into the ECU as per the diagram downloaded from here.

My car already had an ancient turbo timer in, and I used the harness from that, the only difference there is from the instructions that came with the GReddy unit is that the shift lock release wire is connected, if I disconnect this, the timer will not work at all. Any suggestions?