So what started off as a basic oil and filters (air, oil and turbo oil breather - it's a diesel) change ended up being an hour's worth of frustration.
All the 5mm allen bolts came out fine except for the very rear one of the air filter. You know, the one that's incredibly awkward to get to.
The previous owner/garage must have damaged them because as I tried to turn it, it gave an almighty bang and all edges of the head of the bolt seemed to be stripped!
Does anyone have any recommendations as to what to do? I can't remove air filter housing easily as it's just that one bolt held on tight. I thought about pulling hard and hoping the plastic housing tears in the right place, but I guess worst case I buy a new air filter housing. It's either that or take it to a garage, unless anyone else has any brilliant ideas? Have used WD40 on it, no success. As a very last resort I thought about gluing the allen key into the head of the screw but the amount of torque is probably going to rip the allen key out of the bolt :(
Oh and to make it worse I tripped and knocked the magnetic bolt holder full of engine cover bolts into the engine bay - still missing 5 of them!