Sometimes i surprise myself...
On the other thread Wally kindly put me in contact with a Dutch man who pointed me to an Italian man who could make the tester €180 plus delivery.
Now you have to work hard to get €200 out of me, so i went to Halfords and spent £20 on wire, a couple of switches and some connectors. It might be not pretty but the CEL light started to flash.
About 10 rapid flashes
Then a steady 3
2 second gap
Then a steady 3
Rapid flashes again to signal end of message.
It repeated that several times. I am not 100% sure whether i was reading from either bank but TPS was the obvious thing judging by the above post.
I have a video showing flashes but is a bit big to upload, although just a flashing light i was quite pleased with myself !!