Further information from Alec.
"I have done a bit of research on the IOW Poster with the Lancia ‘Charabanc’ and think it could well have been an Island registered vehicle. In a book, recently published by Mark Chessel, he lists known Island registrations back to when records started. A Lancia “RTC” 14-Seater Charabanc, body by “S.W.M.Blundell”, Reg No. DL 1807 is listed in 1921. In another book by the same author, there is a list of “known to still exist” DL numbers but DL1807 is not included, so there is no photograph, so could be the subject of a “Where is it now?”
I hope this may be of use."
P