Now to me a track rod end and a drag link end are differant, as is a tie rod end, However it seems that the only criterior is "is it LH or RH thread is this the case on a dicovery 1 IE are the threded rod ends interchanable from track to drag or tie evenwhich to me has nothing to to with steering at all
Devlin,

There's only one LH thread ball joint, that's on the N/S drag link the others including the track rod ends are RH thread and yes joints are the same other than the thread although there two drop arms one has a combined ball joint (early D1s).

Thanks for that Dicool I have found out the hard way, "yes sir we have them in stock" Now for me that means an extra £7.00 to have it sent over on the ferry So I get it at 2 PM and yes it was the N/S and they sent a rht, by the time I get the thing off (oxy propane job) big ring spanner and stilsons, quick clean up, open the box and "AH BUGGER", one bad tempered phone call to a perfectly reasonable chap at the factors and its all put off till tomorrow, still I changed the oil and filters cleaned out the crap trap so not an entire wasted afternoon, which all means if I go like the clappers for the rest of the week I might make the pub on Saturday afternoon
Devlin

I found out the "hard way " also two years ago.

When I had to replace the same LHT ball joint again few weeks ago because the of "slight wear" according the the mot man (that's genuine parts 4U) it took only 20 mins as I previously copper greased the threads.