Hi Alan from Devon
MOH (my other half) and I don't hold to be XJS experts, but we do own a '92 4.0 Phase One facelift, as per your dad's, alongside our X150 XK and S-type.
It seems that the parts you are talking about are all available from SNG Barratt, whose website is very user friendly and well illustrated.
1. anti-roll bar link complete C42907 £67.79 (also available as repro part C42907* £30.00 ) (all prices inclusive of VAT)
The bushes are available separately C42907/1 @ £5.40 each but then you have to pay labour to remove old bushes and fit new
2. Suspension arm pin/bush, front upper N/S
Sounds like the Slipflex bush CAC9295 £32.53 (repro part CAC9295* £8.81)
Probably best to also renew washer C29975 £14.16 (repro part C29975* £5.28)
All the above are showing as available; note we don't have any connection with Barratts, other than as customers who live quite close by.
Hope this helps.
By the way, as you hail from Devon, is it true that "the train don't stop Camborne Wednesday?!)
Good luck and happy growling