Hi,
Have you compared prices with other dry cleaners in the area you live in?
Which area or part of the UK are you at? I'm in the Slough and Heathrow area, and I think prices range from around £3 and up for a shirt.
Like any business, there is and can be variance in pricing. Also, in 'general' in the UK prices are higher when compared to the USA.
Cheers, DtM! West London & Slough UK!