Hi Richard,
How do you know it is one of the layshaft bearings?
If it is, the one at the front is easiest to get at, if not then then one at the back (just before 5th gear) requires an almost full strip down.
you will probably need bearing splitters/pullers (or a grinder and chisel) to get the old ones off.
you will need something to press the new bearing on with (sometimes they can be "drifted" on, being careful not to stress the actual bearing races).
there is quite a lot to do,and some fiddly bits , but it is nothing too hard.
keep everything clean, don't let the springs and slippers from 4th gear syncro (the first one near the input shaft) boing out of place and get lost.
i would suggest you get a decent manual (or pdf manual) showing all the bits and where they go.
the transfer box and gearbox are quite heavy, you might want to get help of a crane to remove them.
if you are replacing the clutch, then you can use the gearbox input shaft (once you have stripped the gearbox cover off) as a clutch centering tool.
cheers
Stephen