I know the site rules say "don't reply to old posts" but I was searching greenteaguru, having just received my first order and I saw this unanswered request for feedback...
Oli, the site looks fine to me. Navigation is straightforward and purchasing was a breeze - I liked that you had several raw Peurh to choose from and I have just taken possession of 3 samples, as well as 3 other teas (and a bonus sample)! I am just on my 2nd brew of the first one - the http://www.greenteaguru.co.uk/shop/raw-pu-erh/certified-organic-2006-mengku-wild-arbor-king-raw-pu-erh-cake/
I have been mostly buying my tea from Canton Teas recently and I use my order history to refer back to the teas that I am drinking. However, once they are out of stock, the links tend not to work. One thing I would ask of your site is that you keep all the history of teas you have sold - when you buy a whole beeng cha with the expectation of keeping it for several months at least, it's frustrating to lose access to the tasting notes, reviews, etc!
I also particularly liked the fact that some of the teas had dedicated YouTube clips for them - this is a really nice touch and is genuinely useful.
Before this order I have owned 4 raw beeng cha (and various other teas of course) and I have a pretty good idea of what I like but I certainly don't have the vocabulary yet for a review of what I'm drinking, but I will certainly let you know what works for me