Since the missus's car also took longer and longer to fire up on starting, decided to replace the glow plugs today, nothing else constructive i could do in weather like this. 
The 2 rear plugs were a P.I.T.A to get to. Torque specs were 18 nm, this felt like a hell of a lot on the 1st plug, so decided to go 12 nm, wasnt keen on breaking off any plugs today, also have been soaking the old plugs with WD40 the last few weeks, made removing them sooooo much easier.