I don't get why UK key caps has to be in a vendor sub forum whilst US based vendors can post in the group buy section... Maybe adopt the same approach as the others? Low mark up for initial group buy participants and then bump up the price by 25% once the initial group buy period is over? I live in the UK and so I appreciate not having to pay for international shipping and customs charges on stuff that originates from the EU!
You basically answered your question in your post, but if you still have questions from a moderation perspective we're always willing to comment on that. Sales/buys that have significant community input and/or offer economies of scale discounts will be permitted in the GB forum, while strictly vendor ventures will be placed here. Of course there's a bit of a grey area in between, so if you ever feel that a bit was incorrectly placed, let us know.
PS it has absolutely nothing to do with where the vendor operates out of.