Is this the older IDI engine? if so sounds like something interupting the fuel supply, have you changed the fuel filter recently?

engine wise its a 1.8 turbo diesel 8valve duratek i think and yes fuel filter changed around 12 weeks ago . but only noticed problem a curing in last 2 weeks . it will start and run perfect from cold when it starts to warm up it gets quite bad blue smoking when it does it but seems to get better as engine get to norm running temp . thanks for your interest in this matter any further assistance would be appreciated thanks again in advance . Neil .