Ok, I hear this has a broad meaning but need some advice. Car starts first time, easily. Increasing amount of smoke when cold only and running idle is rough. Glowplug light starts flashing only when accelerating over 2500-3000 rpm in 4th or above, 1st to 3rd no problems. Car can be driven with light flashing but on some occasions it has cut out and taken a bit of foot and gas to get going after which ok except for above. Recently changed oil, oil filter, air filter..not fuel filter as nit that old as done before being bought. Changed camshaft sensor today, problem still there.

Common advice is that its injectors but before I consider that expense is there anything else this could be?

I hear a leak test or blow test can be done, what is this and how is it done? Sorry, loads of info and questions but need to try and understand what's happening :-(

Thanks

check out the 4TH link here on how to do a leak off test.

put - Injector Leak-Off Test - in google search

Thanks for that, only problem now is my engine management light has come on!! Am I in danger of the car failing if I continue to drive it?

It certainly won't be doing it much good.