Sorry , juts seen your earlier comment about ballet pumps. I think those M&S boots are a bit too classic in style BaronessOrcry. You need a more funky wedge like the one Oldbride is suggesting I think.
What like are the combats? Do they come up higher on the waist than normal? Are they really skinny in the leg? I was going to go for a 16 but if v skinny - I'd get an 18 and get them taken in. I can't carry off too skinny a leg. I like the wedges Oldbride linked to. Or Blowfish do very similar type wedgy boots that would be nice. www.rubbersole.co.uk/Blowfish-Wylie-x103707.php they have loads of others that look more or less the same in case you can't get your size in one style.