Well I wasted a day today.
Set off first thing to drive 9 miles to get alignment done, but after a few hundred yards it was apparent the handling was simply appalling. Panic sort of set in, I was wondering if the tighten-loosen-tighten procedure on the hub nuts had gone wrong and I was perhaps wrecking my wheel bearings. Turned round, jack out, checked there was no play in the front wheels. None. Another short drive and I still wasn't happy so I postponed the alignment.
I decided I'd set tracking up a bit better, but this ended with a 60 mile round trip to acquire an M14 x 1.5 flat nut to use as a locknut on one trackrod.
After this, handling feels perfect, generally nice and solid.
(The moral of the tale.... Too much toe-in = scary handling).
Also my wishbones are now a lot nearer horizontal than they were before I changed it all.
Alignment tomorrow.