The only thing inherantly weak with the Td5 axle is the CV joints.
I say "weak", well, they're weaker than the earlier 23 spline (commonly referred to as the AEU2522 CV's),
but: This "weakness" kind of comes from the area of people who use rovers for challenge events and such. for general off roading, green laning or overland like you do Darrin, They will be 100% fine (after all, LR are still fitting them to the even more powerfull 2.4 TDci engined vehicle)
I've got the same axle as you're looking at, under the front of my chipped-to-175bhp 110 with front ARB locker and 255/85 tyres, and they're fine.
Like i say, I think you'll only start to see problems if you'r hoofing around on 35" simex tyres.
As for being a straight fit onto your 110.... the later (300Tdi onwards) radius arms are slightly wider, so if you can get those as well you'll need them. The extra width is where the bushes are (where the axle bolts on), it's only about 5mm or so, but it's supposed to tighten the front end up slightly.
And I think, most Td5's had vented front brakes too, so you'll gain from that; Brake pipe unions should be the same size though.