Bit of an update as it took a little while to do!
I have just finished assembling and soldering the Speeduino itself, complete with a VR conditioner which is used for when a VR sensor is being used to monitor the trigger wheel on the crank pulley - still need to measure and make this, then get it welded/bolted onto the original pulley. I think I stayed up til about midnight last night, probably took me 4-5 hours in total to get everything all together. Still need to hardware test with a 12v supply to the board, but for now the ignition lights work and can't see any smoke so going to test with 12 but assume it's OK for now. Here is the finished unit:
Aside from this, as an overview, I have circled what I'll actually be using for this project. I still need to make an enclosure for the ECU and figure out the nicest way of making a plug that isn't a 40-pin IDE ribbon cable.. thinking of using some of the bosch weatherproof connectors for each row of the 40-pin. Anything else I'll probably make up as I go along as I'm not sure what other things I'll need from the board. For certain I am going to be controlling the fuel pump and a thermo fan, both of these will just be powering relays.
Have decided the best self contained way of doing fueling is to use a low pressure fuel pump, sat outside the tank, going to high pressure fuel pump which will sit in a swirl pot. Not sure what i'll do for venting the tank just yet, need to pull it out and see if there are provisions on it like there are with a spitfire.
Still lots to do but feel like I'm making a bit of progress!
Edit: a basic hardware test went well, I have spark + fuel!