Hi guys..
Bailes1992...you'll have to let me know how your car ends up after glow plugs? But did you car throw out constant white smoke?
Lee Palin. ..my car has gone back to the shitty same problem. I had a 2nd hand ecu fitted as a garage said it could be the cold start on the computer and nothing showed up on diagnostics as the computer would find a fault with itself. Anyway this solved it all for about a week or 2. So I'm still none the wiser I got fed up n just drive it now BUT it's still going even though it has the same problem.
Sorry this isn't much help but let me know if you do find the problem.