[Sir Henry] It may be now, but my 3d (3 old pence) "Souvenir Platform Ticket" (148mm x 50mm) has it as one word. Also I seem to remember that the Guiness Book of Records, (Longest place name in the UK,) has it as one word.
Liskeard
Gdansk
Skegness
[Sir H] on some cheap maps it appears as "Llanfair PG"
Writtle