I had (issued!) three different type of early high leg boots in the 70's & 80's;
1, The NI issued boot, different sole to DMS and NO toe cap, 1979.
2, Boot Combat High, NO toe cap, 1982.
3, Boots DMS mit toe cap with extentions from a pair of Doc Martin boots and side zips, knocked up by the Choggies in the Kesh in 1979. Mucka Gee, Mucka Gee, Cheese & Egg Burger to go.
The boots being sold as high leg DMS with a toe cap were available as a private purchase from Army & Navy Stores and similar shops in Aldershot in the 70's and 80's. Did not stop some RSM's making you wear puttees on top!!!!
Of course any squaddie who had served in German had a pair of the German Para Boots. (For exercise purposes only!!!).
If you live near to Milton Keynes, I may be able to do a deal for some of the other bits you want.