Umm ... I feel very sorry, that you have to avoid that shop. I don't think I give the aura of extreme wealth, and I never just buy anything that the SA show me. My tactic is: Just stroll in carefreely into ANY hermes store in any country and have always been treated nicely and all the SAs been friendly to me. I am almost always never neatly dressed. I have been in the shop in Cannes in flipflops and shorts and been offered to buy a pale blue Birkin 35 without any previous purchase history in that shop, I just walked in and said I wanted to buy something that will make me remember this particular shop forever. All I know is that the SAs likes me, even on first glance, I have been told by all of them that I am friendly and funny. They feel very relax showing me items and knows that I will always be delighted. So, perhaps being less tense or serious helps.
I have a not so good experience with Sloane street, they seemed very indifferent , and I never went in there asking for either KB,
NBS are all very nice and helpful, but I was only offered a Kelly once, and I declined as it was the wrong Colour, but I was never offered again,
Harrods are very nice too,but it's always too busy and I'm not a fan of shopping at harrods, so I ignore going there, but many friends swear it's the only place they get to buy Birkins Ofcourse they buy lots of Jewellery from hermes so maybe that's why,
Selfridges are probably the best in terms of service IMHO, had a great experience a couple of months ago with them, and recently they called to offer me a kelly, but it was the wrong colour and size for me, nonetheless the SA was so sweet and promised to call again if anything in my wish list come up,
A very important matter is that stocks are generally very very low for a big city like London, I've mentioned this before I think, but I know some people who started shopping in places they frequent like Zurich and Frankfurt, and they find it much easer to get bags there than in London,