To finish this thread off now. Project Tonga 1.8 went to a new home tonight.
It's strange isn't it.
I bought her as a replacement to my misbehaving SE auto, only to find the fault on the auto (fingers crossed!!), so now sell her on as I really do prefer the drive of an auto box.
Still it looks like project Tonga has gone on to a good home, and will now take up a new role for the future.
Goodbye Tonga 1.8, and all the best for the future.