Right, at the weekend I dropped the glowplugs out and shorted them across the battery, glowing red after 5 seconds. Also tested battery voltage, 12.3V across terminals, voltage at glow plugs 11.9V, voltage at battery with everything on at tickover 14.3V so alternator seems to be charging ok, is 12.3V a bit low and would it be wise to replace battery? also, following the warning about the starter motor, if the engine was cranked before the glow plugs got hot the power to the plugs would dissappear. Anyway, current situation is turn ignition on, wait 5 seconds then crank and engine starts on second or third turn.
Thanks for all the advice