Yesssss!!! Installed the new rack and clunking is goooone!! Took me about 4 hours on Saturday to pull the old rack out, mainly undoing lots of crap to get the subframe to lower. With supercheap balljoint splitters, wasn't even 30 secs to get both ends out. Eventually got it to budge 3/4 inch at the back, then stuffed around with U bolts for a bit, but eventually, the wretched thing was out! If I hold it like a dumbbell and shake it, the rack inside plus both ends clunk around independently of the body, feels like about 1/2 in play. In contrast DrMini's rack is one solid block.
Next day, I adjusted the new rod ends as per the old rack, measured the threads, also measured end to end, then installed the rack in. Getting the U bolts back in wasn't as hard as I expected. My car has U-shaped plates which goes on the other side of the rack, between it and the body. What was a **** bitch of a job was getting the steering column bolted back into the crossmember. I followed the advice of not tightening the U bolts until the column was in and locked to the rack.
After that it was a another **** POS to get the lower subframe bolts aligned with the holes, and getting a spanner on the inside and a ratchet from the outside. Wish I was an octopus!!
Then I did something really dumb, I thought that the hubs weren't straight so I backed out the tie rod ends a few turns. Of course when I put the wheels back on, it was obviously wrong. So I pissfarted around getting them back to roughly straight (wish I left them alone). Spent yonks tightening everything up again, feeling really tired and sore after two days of this. Pinched my finger in the door and now I have a bruise.
This morning I got my wheel alignment done for $60, and

Went for a lap around the track, been doing unnecessary detours around roundabouts, doing 3/4 turns to turn left .

I forgot how much fun it is to drive.
Steering is still quite tight, I probably have to wait for the rack and new rod ends to bed in. It's not righting itself easily because of that.