I'd echo the above.
Discs and calipers, brand new, probably wont run to more than £150 and second hand calipers would make that much cheaper.
Having swapped an axle myself I would sooner do it the easy way. And knowing your own axle is a good one is nice also.
All that said, if you've got a decent workshop, ramp and helpers and the axle is known good and cheap then go for it.
Stu.