Help with Gearbox

Can anyone help me.
My series 2a landy with a Defender gearbox needs a new layshaft and reverse idler gear. the problem is the gearbox only has 50A stamped on it.
Does any have a list with the number of teeth on the lay shaft cross referenced with the part number so i can identify and order the layshaft.

thanks
Kev

50a should have the same number of teeth ,51a or 56a are different what suffix is box d,e,f,g,h?

That's the problem it just had 50a 6889 stamped on it. This has been stamped over the original numbers.

50a is usually 34 teeth on pinion gear ,but so will 51a ,56a will have 33 but you need to decide if it has small bearings (identical both ends ) or larger ones (rear bearing has step in outer race)

Ok i have counted the teeth 34 29 19 14 14 the bearings look both the same.