[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
Yeovil (Bloodnok) Llanfair PG is what the locals call it.
Ashton Keyhes
Little Dunmow
Wookey Hole
Bere Regis
Fawkham
Denton
Bootle
Horwich
Diggle
Sleaford