finally got the new bushes(correct size this time) but in the meantime while waiting for the bushes I replaced all 4 ball joints with heavy duty Synergy units, (the bottom 2 were really loose?) also replaced the drag link with a heavy duty Synergy unit, and steering damper from teraflex with relocation bolt which replaces the bottom track bar bolt.
All seems OK with no more death wobble, just a shake like wheel balance, so getting the tyres checked will be next, but it's definitely better.
Andrew