Actually if the circlips you are reffering to are the ones on the half shaft you can buy them from Ford. If the special tool you mentioned is the one for pulling the half shafts you can accomplish that with a helper and a large screwdriver. You just need to get some outwards pressure on the halfshaft to get the circlips to compress into the groove of the side gears of the diff carrier so they (the half shafts) can be removed.