Soooo, had to replace the battery, Halfords 110 efb 75ah 735a, £114. Would’ve got the Bosch s4 E10 but needed one like yesterday!
tested before fitting 26.7v, old one 0.00v wouldn’t even give me a reading. Old oem one is on charge with the ctek to see what happens with the readings when charged, just for interest really.
and stop start works again. Think I’ll recon the battery on my 65 plate 1.5tdci when I get the time.