Well you need to drop the gearbox out, so I think you'll need 3ft high axle stands at a minimum, along with rolling around on the floor, and somehow controlling the weight of the gearbox. Unless you go for the engine out route, in which case you still need to get under it to disconnect the gearbox to engine bellhousing bolts.
No idea why they won't do it. Craig at H-dev did mine in 3.5 hours, ish. If doing it yourself it would probably take a day. I just didn't have the time.