Just a quick update, I have just spoken with Ash as he was driving down the A303 to drop the car at the show.
He went to CBS and got two lengths of
beaded aluminium tube then fitted them and ran the car up to temp, whilst stood in the kitchen.
The upshot being the fan cut in and the rad cap was venting. So as we suspected our hose connection was to blame.
See some of you guys tomorrow at 1pm, I will be the slightly sun burnt one.