Ok - got the old seal out, just tapped around the rubber part of it a tad with a flat head screwdriver, came out pretty easily.
any seal that will fit will do, not like the axle is rotating at any speed, maybe double if if you can get it in the size.
Norm when you said this did you mean if the space allowed it to place two seal in rather than one? i.e one could place two 1/8" thick seals rather than a single 1/4" thick one. I only ask as it almost appears there's another seal in behind the one I removed - looking at the gearbox assembly diagram I can't see exactly what it might be - is in too far for me to remove, but a tad curious, can see a slight amount of gearbox oil leaking out under it - whatever it is.
The old seal that was removed appears to definitely be the 1/4" thickness.
