Assualt boots are nothing like as bad as a lot of people pretend to think!
You just need to give them some smooth lovin', know how to wear them and make sure they fit properly. You may find surgical spirit does wonders for soft feet, especially if you aren't used to leather shoes; most people wear trainers these days, and frankly you couldn't have worse preparation.
Assuming you've got exactly your size, then fill them up with water and leave them overnight. The next day, empty 'em out and go shopping or something (some would say bag some peaks, but not by yourself and not if you've got foot problems). Keep them on until dry.
Your boots will now be shaped to your foot. Next phase is called "never take them off". Keep them on all the time, a process which can be accellerated by wearing them in bed. This is a good time to get some easy hillwalking in.
Surgical spirit rubbed on your hooves morning and evening will soon make them suitabley horny, if you feel you need it, and always make sure the laces are properly tightened, all the way up.
Learn how to wear issue boots and you'll save a fortune on bloody Lowas. Think: issued boots have probably never been this good, and there is a long history of Brits doing far tougher stuff than you'll be facing without worrying about poser kit (pace Boots Combat Leg High, which are a British Procurement Mystery and best forgotten).
And Johnny Afghan cuts about the battlefield in home-made flip-flops, so anyone who tells you a boot somehow needs magical powers to be any good is probably trying to sell you something.
Or has just been sold something.
(If, on the other hand, you MUST HAVE THOSE SHOES!!!, then try getting the MO to sign you off with biff feet; Lowas will then be yours for the issuing and the RSM will just have to choke on it).