It IS possible to get Mk.VII bullets for reloading in the UKbut they are horrendously expensive because the guys essentially hand make them.
Frontier of South Africa make a 174 gn. CMJ flat-base. Due to its design, it has a huge bearing surface which is all good but it also resembles flying dustbin and so I do not expect it will be much good at the longer ranges. The UK importer is a guy near Armagh City.