I agree with Octy, look subtle, don't tell them your life history as soon as you meet them, this shows a lack of breeding, really posh folk assume people know who they are!!
If you can, wear designer shoes, tie, but look on ebay and get them cheap!!!
Wear an old school tie if you can find one, but only if you know the motto and a bit about the school!!
I donl;t mean you should lie, or fanatasisie, but let them know you have 'connections' and be mysterious.
I am being nosy now, but what sort of meeting is it?
(If I don't ask B00 will )