Update:
She comes home!!
The last two days were implementation of the revised pedalbox and complete construction of the exhaust system.
The pedalbox went in perfectly and works fine, however the biting point of the clutch it right at the bottom.
The exhaust was pretty uneventful too apart from the welder breaking as I was welding the last hanging bracket (managed to sort it though).
The original plan was to use a factory 24v backbox, however I failed to factor in the fact that my carlton is an estate and the backbox I sourced was for a saloon (so the BB fouls the rear shocker). So using that backbox was a big NO, unfortunately the only other box I had which would fit is rather... erm.. small shall we say

Pics:
First off I raised it at the rear... a lot:

Shot from the N/S sill:

The whole system hugs the car very tightly, it gets within 1 inch of one of the CV joints:


The completed mid-section:

Here is the completed exhaust, the mid-section has been fully heat wrapped. The backbox is clamped before and after to angle and length adjustment:

After the exhaust was finished I cleaned up the engine bay, refitted the bonnet and drive home, problems arose:
The engine had a bad misfire under any sort of load
The electric windows wouldn't work (so they were stuck open)
The throttle cable popped off
The electric windows were down to my colleague forgetting to connect an earth point down in the passenger footwell and a ziptie will stop the throttle cable popping off again.
The misfire was down to spark lead no.2 dying, a suitable replacement was found in my garage

I have also bypassed the heater matrix due to one of the copper joiners leading to it leaking, the matrix is pretty knackered anyways so I have decided to replace it. Can you still buy them new??