Thanks guys, bad news but good to know.

Back to the spanners.

Cheers. MY11 SD4 SE Auto

I changed my glow plugs when I removed the swirl flaps in my intake manifold and still no joy getting the plug light to illuminate.

A couple weeks later I started having boost problems long story short brought an OBD II reader and there was a fault on the ECU for the glowplugs (cant remember the code).

Cleared the code and when I cycled the ignition supprise supprise the plug light illuminated! It was very mild outside about 14c funny thing is it new illuminated again until the temp hit -1c.

Might be worth reading the codes and seeing if there is one that needs to be cleared to allow the ECU to warm the plugs up?

Yes I really do need to get a code reader and clearer if I'm going to carry on messing with cars. What do you have? MY11 SD4 SE Auto

Trust me from a "Nerd" perspective its wonderful the information you can see is great. I brought one of these:

https://www.amazon.co.uk/gp/product/B01N30...&psc=1

Used an app called Car Scanner from the google play store you can read and clear codes without paying brilliant as a cheap fix but I ended up buying an app called OBD Mary worth every penny the interface is so clear and easy to understand great app