Td5, 90,handbrake

Hi all, have an 03 90 diesel 5 speed.
Every year for mot we have to remove the handbrake drum as the handbrake wont hold and the shoes are drenched in oil.
The flange is unscored and we fit new seals plastic ones and felt and we seem OK for a month or two. The universal joints on the prop seem good and there's no play on the rear bearings. Anyone have any suggestions?
I'm wondering if there's a gearbox breather blocked somewhere. If so where is it?
Had series 2,3 etc and never had this problem. The td5 doesn't tow anywhere like the old ones did.
Many thanks

Speedi sleeve.
Stopped the leaks on the my s2.
I feel the felt seals on their own are a waste of space, cannot hurt to apply some silicone sealant to the splines then fit the felt seal?

The breather comes off the top of the high-low selector mechanism on the forward facing 'nose cone' of the transfer mechanism. The rear output oil seal seems to be a common failure point on these. I've replaced mine several times. To get a longer life out of them, try and get a famous name brand like Corteco, rather than the Britpart own-brand items which can be disappointing. The drive flange itself isn't too dear as I remember, so it can be worth putting a new one on when you change the seal. Sometimes you get one that just doesn't want to make a good seal, despite looking smooth to the naked observer.

Not really a solution to your oil leak as such, but have you thought about converting the drum to a disk? I did it on mine and it holds much better plus will be much easier for you to clean.