Well Huw, I'm not sure if this is the right part but take a look here:
http://www.rimmerbros.co.uk/rimmer/rove ... a/steering
By way of short explanation, Rimmers have a whole boatload (literally) of Rover SD1 parts that they repatriated from India, not that long ago. All these parts were rescued from a factory that had been set up to assemble the SD1 in India, but the project flopped & for many years this huge pile of parts was just locked away in a disused factory.
These PAS racks are from the right era, & while they are not going to fit straight into a TR8 they may be what you need for the conversion. Maybe someone else can offer advice on the suitability.
Tony
<font size="1">1981 2L FHC Cavalry Blue - very original & not rusty!
1980 3.5L V8 DHC Regency Red - on the road again.</font id="size1">