Good point about Ebay. So I turned to the web and first site I found was "BuyCarParts" who have the tag line "Trusted Car Parts Retailer from Germany". But I'm now faced with at least twenty choices! From cheapest upwards they go like this: Ridex, OMG, Reinhoch, Vaico, GT Bergmann, SKF, Moog, Magnet Marelli, Sidem, MS Germany, Dys, Spidan, Fraft Automotive, TRW, ABS, Mapco, Denickerman, Stark and QH.
I'm sure I've heard of Vaico, have definitely heard of SKF (obviously for bearings) and only about three or four of the others. As this site has the registration number lookup I guess I will go with SKF at about £40 each incl VAT but excl Delivery.
Unless someone on here can recommend a different supplier for a quality part. Sometimes you just have to take a punt I guess.