At the Harrogate show i'm sure I saw a product for sale on the woodworkers workshop stand that might help. It was a slippery plastic, about 2 inches wide, very thin, self adhesive backed. Prepacked in a length that I guessed was between 18" and two feet.
My suggestion would be to look at putting plastic rubbing blocks in the bottom of the fence. That way you don't need anything on the bench surface. They only need stand proud by a millimetre. There's probably a recess that you could seat something into. Cut some nylon or HMWPE "slick" strip to suit. Or get some nylon bolts and tap the bottom of the fence to take them, screw in then sand the heads down until there's only a mm standing proud below the fence.
I have an old kity mitre gauge that has four push in plastic plugs in the bottom edge of it's fence. They serve the same purpose and the mitre gauge slides smoothly over the tablesaw's cast aluminium top without scratching.
