Out of all the series which featured the curiosity shop as the starting (and ending) point of every series only Wonders In Letterland features scenes outside of the shop. The inside of the shop was a set (used throughout the subsequent series up to T. Bag and the Rings Of Olympus). The starting scene of Wonders In Letterland was filmed using the exterior of a shop in Twickenham in London. The shop is now called 'Papillon' and was probably the same shop when the scene was filmed.
Well the shop is still there in Twickenham and I've got some photographs of the shop exterior - it has hardly changed (maybe only a lick of paint!) The door is still the same and so is the window. Have a look at the photographs below in comparison to the shots from Wonders In Letterland. I'm hoping to get some footage soon - watch this space!
If you want to go see the curiosity shop, the address is:
Papillon
37 Church Street
TWICKENHAM
TW1 3NR
Many thanks to Paul for finding the shop (after searching through half of London) and for his photographs of the shop.