removal of standard seat covers

Apologies if this is already posted somewhere. I want to remove the actual seat lining so I can clean it and re-stitch parts that have come undone. has anyone done this before? I have the phase 1 standard seats and only want to remove the front two bases which you sit on.
Also need some replacement foam that holds up the side walls if anyone has some?

I can't remember anyone doing it diy unless it was through a shop. Not sure how difficult it would be.

I took the bottom of the seat of a spare drivers I had a threw the rest as the rest was scrap. Could have a look at the weekend to see how it comes apart if it does, the bottom does come off though but the mechanism was f00ked on this one so unsure it helped with removal etc.

Easy enough, remove the 'hog rings' that hold the fabric to the lines, clean the fabric and then use this to put it back in place.
http://www.ebay.com/itm/Hog-Ring-Pliers-and-SPENAX-Hog-Rings-3-4-for-Upholstery-Seat-Covers-USA-MADE-/182230840715