Hi Tommog,
I removed and refitted mine for a reflash.
Firstly disconnect the battery.
The ECU is the lower unit in the aluminium box in the RHS of the engine bay. Disconnect the top unit and remove it, it is Velcroed on top of the lower one.
The ECU is fitted in very closely and you will need to move the loom aroud to access the 4 bolts which secure it.
Once the bolts have been removed you move the ECU around enough so that you can release the levers which retain the two plugs.
It should then wiggle out by moving the loom around. I think I also had to lift the fuse units off their retainers to provide enough movement.
Fitting is the reverse but be very careful not to bend the pins.
