Thank you so much for replying, really appreciated.

The glow plugs have been replaced with 2 different sets, both new, I think it does smell like fuel a bit, I'll try and get a better whiff of it next time.

A week after buying it (18 months ago) I think it was 3 of the injectors were leaking, he glued the others back in (somebody said he should not have done that ? ) and replaced the seal on one of them, then began leaking from leak off pipe, he put cable ties around the injectors to the Leak off pipe , no visible leaks since.
However I feel my economy is poor, averaging 38-40 mpg driving within speed limits mix of around town and short motorway trips, the mpg statistics for this car is 39.2 mpg. extra 64.2, combined 52.3

Car chugs on idle sometimes but does not affect performance of the car, goes away when bring clutch up also. first noticed this noise the day I purchased it driving it home.

so, could it be injectors, could it be a sign of head gasket failure ??

Thanks !