as for the heightmap it hasn't really got anywhere yet as we need some people skilled in it, hence why I've been advertising for modders etc. but people to do the Heightmap and landscapes are our main priority atm
This is the part where you learn to do things yourself. No one is going to join a project that is just music, some models and no landscape. You need to show that you yourself are working on the mod, and are prepared to do everything yourself if needs be. You can't expect someone else to make a heightmap of the whole of England, it would take an awful lot of time, and for something that no actual progress has been seen from, that is a big, risky commitment.
Start making the heightmap youself, even if it's just a practice ona small part of england, and then get used to it. Then show some results, and more people will likely join.