Glad to hear its sorted. A blocked axle breather can also cause even a new seal to fail and let oil past, was the breather checked at either of the two earlier attempts? As you say, there could also have been a problem with the land on the pinion flange where the seal runs, causing premature failure. Did Mr T replace the pinion flange as well this time?
Anyway, I hope it's sorted longterm this time and seeing as you have two very experienced 80 series guys local to you, I'm sure you'll be we'll advised on the joys and easiest path of Land Cruiser ownership!