what looks different on your then?
ok if yours is a disco it will have rear discs, but the internals of the wheel hub should be similar
a bearing would keep coming loose if:
it was new and not propely bedded in yet. keep resetting the preload until it doesnt loosen anymore
it was not tightened up sufficiently in the first place and keeps wearing loose
the bearing outer races have not been driven fully home and so are moving inside the hub in use and thus loosening the bearing preload in use.
the wheel hub/bearing components are damged and so the bearings are running out of true, or it is a bad bearing that wears.
ive done quite a lot of bearing folly in my land rover time, so let me know whats up i might be able to help.
cheers
p.s. bigbenny have you got a salisbury back axle? if not i have a load of 10 spline spares, stubs/disc hubs etc