Did anyone successfully replace the cat section (gems) on the driveway? Local garage wants 200 quid...I assume the tricky bit is going to be supporting the gearbox and then pulling off the x member. I trust my impact wrench to get the manifold nuts off...spare studs on standby, and new lambda sensors

Yes, crowbar to get the crossmember off (with a jack under the transfer case) and lump hammer to put it back. The only problem might be having to drill out and re-tap (M10) the threads when manifold to downpipe studs shear off.

You can buy an inexpensive 3-part cat pipe set on eBay which seems to do the job. If you chop up the old pipe (mine actually just fell apart while trying to remove it) you can fit it without dropping the gearbox.