Well good news is that it passed an MOT! Will get back into fault finding in the next couple of weeks. In the frost I thought the battery was going to run out of juice before it would start!
Well little development. Seems like I'm losing 5th gear, getting v noisy. So I'm pussying out of the fault finding! Have a rear damaged D2 td5 with low mileage so I'm going to straight swap the engine and box, at least that's the plan!