When it comes to where to locate the ECU, for what I have seen it varies depending on who is doing the conversion. I have seen them in the cabin behind the seats, inside the wheel arch liner, in the boot and so on.

I decided to mount mine on exactly the same place as where the original one was. This was really driven by the fact that I wanted to ensure that all the original wiring could still reach and remove the any added complication with the loom make-up.

Another word - LAZY!

The only concern I had with this location is the proximity to the engine and the effect of the heat/ water may have on its operation. So after some head scratching, I decided to make up a cover with some of the Nimbus I had left.

I then marked up the sheet and measured the required dims...

Then it was simply a matter of cutting the shape out and rivet the lugs to hold it in place...

Trial fit and all seems fine...

Add some rubber edging to stop it from cutting through the wires

Push fit into location...

I think that will offer heat protection and keep water away from all the open ports. I am pretty happy with that and I can call that job done!