I am looking for floor gliders for double sliding wooden doors. We are replacing the old doors and have the track but are missing the gliders.

It is likely that the gliders we supply will be different to those on your existing doors.  The only ones we do similar to your description are the white plastic slides which are used with the BK2 and BK4 bottom guide kits, and they can be bought in pairs for £1.25 per pair (+ postage & VAT) if they look like your old ones.