When I'm looking for bearings and seals for my Pommy made tractors I take them into the bearing shop all nice and clean so the counter jumper doesn't get a bit of dirt under his finger nail and they look for the number and if none are found then they get out the calipers and measure ID, OD and width, they have always found a substitute.
An example is the front wheel bearing on my D.B. Cropmaster. They used some real odd angled bearings originally and the guys then did the measurements and plonked a set of bearings on the counter exactly the same sizes but a different angle for the bearings which made no difference. So get them to think outside the square and go with the sizes for a replacement.
Anthony. Those seals are available at just about any good bearing/seal shop. Easy to remove, just about punch them out with a wooden dowell and hammer. Unless it’s totally wrecked, take it into said shop and throw it on the counter. Replaced a couple recently myself, had no trouble getting them. Dave
Meant to add, when you remove the input bearing housing to replace the seal, measure the thickness of the gaskets/shims between the housing and trans case facing. That’s how you set the preload on the input/ mainshaft. Dave