I have seen different Socket sizes used to remove the lug nuts. some are using ASE sockets and some are using metric. What is the proper socket to use with a 1995 Disco with the lug caps still on them and in good condition?

 

Whatever socket fits? Pretty sure I use a 27mm. I only use metric, sae is dum.
Also, here's how I search this site, with google.
google search results

Putting i-39 in the search limits returns to the D1 forum. Or just use the search function here on the forum.

 

1-1/16" 6-point in 1/2" drive with a breaker bar is what I use.
If you want the correct tire tool then you need to buy a Land Rover Discovery tire tool, Ab sells them, like $15+shipping.