Ive been checking out MScs too so been doing some asking around about nerc funds etc, also had the first interview at leeds. I dont know if its the same elsewhere, but this was an informal half day visit and chat with the course director, with half an hour odd of more typical interview. He also said that they give out grants essentially on a first come first served basis - theyll keep interviewing until all the grants are taken by suitable candidates. Again, i dont know if thats the same elsewhere.
As for tips, i guess the best thing is to just make sure you know your career plans and subject area etc inside out, and can demonstrate that youve got your head screwed on. Although they take into account things like prior grades and industry experience, which at this stage you probably cant do much about, i think they like people who have potential and awareness and a good plan, and are not just going for a masters because theyre following the herd. But remember i could be completely wrong as i havent had their reply yet :p
Good luck anyway when you get to the interviews.