is there in Ashfor Kent (or close area) a poster shop where they sell posters from Sherlock (Benedict Cumberbatch) and Dr Who?
The HMV chain sells entertainment posters, the shop in Ashford closed down so the nearest is now in Canterbury (only a 15-20 minute train journey) - I don't know if they sell these particular posters though. If I get a chance I will try to look in the shop for you. I'm not very familiar with the shops in Ashford to make any other suggestions, sorry.
Thanks for your update!
There are a small number of bookshops in Ashford that may sell posters, but there is no specific poster shop. You may be better off ordering from Amazon.
Are you aware of the website www.allposters.co.uk. ? I've not ordered from them myself but their stock is enormous.