It should be easy, but I can't see how to open the box to remove the air filter! All my previous cars have had simple clips or a couple of bolts, but this has got me stumped. I'm guessing you have to detach the two hoses and then it can be slid apart?
Car is a 1995 Astra 1.7 TD (Isuzu engine). Should probably buy a Haynes manual for it....
Cheers
Andrew