Because of the short stop start journeys we do I try to put some good quality diesel engine treatment in the car once every 4 months and some dpf tratment in the tank about twice a year to help it regenerate. If you get a message saying dfp is full and to carry on driving because the car is trying to do a regeneration do not panic, just take the car onto a motorway, country road or long dual carriageway and keep the car in 4th with revs over 2500 and the car will complete it's regen pretty quickly.
Oil % reading on display... this does not indicate how much oil is left in the sump, it indicates the quality of the oil in the sump, the percentage will continue to drop until you get a 'Change Engine Oil Soon' message. Check your oil level on a regular interval, because every regen attempt results in diesel being injected into the sump and the oil level will rise if ignored too long.
If you know how to hold a spanner and socket wrench and are willing to give things a go then I would recommend having a look at the how to's on the forum, particularly the egr, map and throttle body clean tutorial.
https://www.vxoc.org.uk/forum/Thread-2-0...BODY-CLEAN
Gears on the Astra J are prone to be a bit clunky in 1st and 2nd when oil is cold, so don't panic if they feel a little stiff every now and again. In general, the 2.0cdti has the better gearbox.
Glow plugs can be prone to playing up after a few years, the car will still start if one goes. They are easy to replace and the car will clear the fault code on it's own if you do replace one.
If you see a message on your display saying 'Service Vehicle Soon', it has nothing to do with the car needing a service, it means a fault has been found on the car and you will need to have a diagnostic done to find out what it is.