I wore the non Gore-Tex Lowa Sleeka's, they lasted me for the Hill's and a long time afterwards too!
I think they have been discontinued now and replaced by the Lowa Urban boot, these are available in Gore-Tex and non Gore-Tex versions too, albeit slightly heavier.
Ultimately the decision lies with whatever you are comfortable with, i do believe they have to be hi leg black boots, no Jungle, Civvie Hill Walking or GSG9/Bates style boots though, Alt-Berg Sneekers should be fine.
I am with Auld Yin on this one. Best Boots, well bulled are the drill. Make sure you make a lovely crunch as you drive those heels into the parade ground.
If in doubt ask to speak to anyone in the Household Div for advice.
Grow Bags R Us
Whatever boots you wear make sure you buy blakey's and hobnails to go with em, might not be overly stealthy but will make you sound hard as nails anyway so no need to take selection - straight in no problem.