Hi, Rowzie,
Brora - what a lovely place to live - I envy you!
You really should have done some research into places where you can study to be a veterinary suregeon - the proper name of the Edinburgh Veterinary College is: The Royal ( Dick) School of Veterinary Studies, and is part of the University of Edinburgh.
Do not dismiss the Glasgow University Veterinary School - it too is a centre of excellence and is of world class. When the time comes, apply to both - places are limited and not always easy to get.
You are right in thinking that Highers of Chemistry, Biology and Physics ( or Maths) plus, ideally one other subject, are the ones to aim for, and A grades are desirable. At a lower level, the same four subjects plus four others, such as a modern language, English, Computer studies ( almost veterinary all practices are computerised nowadays and a knowledge of computers is invaluable) and history, geography or some other arts subject will give you a good grounding. The University entrance people look at all your exam results, not just at Highers, so a broad range of interests does help.
Contact a veterinary practice somewhere near you - you will get details of local practices from www.rcvs.org.uk - and ask if you can spend some time 'seeing practice', and plan to spend time on farms and other places where you will come into daily contact with animals.
Good luck.
W