If you do a compression test and all is good i would very happy as your gasket will be fine. If that is the case i would be asking how long was the car standing as it may be stale fuel.
So if the compression test comes back fine then i woukd personally buy a bottle of slick 50 from halfords (its like redex only it works) brim the tank with tesco 99 ron. Change the termo and temp sensor. I would even go as far as taking off the throttle body and giving that a good clean.
Then i would perform a good service i.e oil, oil filter, coolent (G12), spark plugs and cabin filter. Then i woild take the car for a really long drive at least 100 miles strech the gears to push the slick 50 around and clean the engine.
If your compression test comes back as a fail you will need to get just hopefully the head gasket changed hopefully it hasn't warped the head.
While that is being done you may as well do the timing belt, water pump and ensure the engine mount bolts are also changed at this point because they are streched bolts and can only be used once.(see my build to what happens if you dont)
Keep us posted pal.
Niño
Hello mate and thank you for all your advice, I went this morning to a friends garage who isn't the best but not a cowboy haha, we plugged the car in on a snap on scanner and it came back with a lambda sensor pre cat fault.
As for the oil sensor workshop warning that has been resolved, the plug had been knocked off the sump as it's low.
The car passed MOT emissions and with flying colours
As for the main concern...... Well it transpires that it's blue smoke that comes out, it's mostly when idle and when starting, once warm it's okay and under load it's not present.
Thee is no loss of coolant and no loss of oil in the last 100 miles
I ordered some bits but I'll wait until I resolve this issue first
Lambda sensor £75
Coolant temp sensor £11
Thermostat £8
Discs front £43
Pads front £30
So no compression test done yet but 2 mechanics say the head gasket looks good