Here in UK the top E6 processor was Metro Color Labs and their service was reasonably priced, high quality and very fast. That was the good news, the bad news is Metro has merged with Ag Photo and the processing charges doubled! Does a British based shooter know of a good value E6 processor with a reputation for quality?
Although not being a "British based shooter", let me put in my two cents. Maybe asking for quality at reasonable prices is demanding too much. It is the usual story behind neoliberal business methods, merging is the euphemistic word for shutting down the lean business branches while doubling the prices by simulaneously reducing costs/services by exploiting synergy effects. The story goes "the customer is king" and those who swallow the bait feel like being treated with appreciative care just because they are labelled "above amateur status" using special gear, taking extraordinary pictures being able to afford the expence.
