Wouldn't it be fun to find out?
So I did some more searching and found, courtesy of Bartlett Library in Falmouth: Part of National Maritime Museum, Cornwall.
"Robb, Arthur C Meteor Yacht, sloop 21 ft LOA - see also CB 2004/04 p 31 Yachting World 1951/03" This looks like it could be the same as my boat.
Falmouths wonderful database showed a couple of Arthur Robb' or Robb A's or similar in their search results. There may have been more than one Arthur Robb: There is an A M Robb and an A C Robb as well as an A Robb so which Robb designed the Meteor?
Update 20120921: The articles [copies available from the museum] confirm it's the same design as my Meteor, that the Meteors were designed for and built at Easticks Yacht Station Ltd, Acle, Norfolk and that it was designed by the famous Arthur C Robb, designer of so many wonderful yachts including the Lion class.
This has been a fascinating journey to track down both the designer and find out who requested the design be built. It is a great pity that more of the Easticks records havn't survived but it's good to know my little boat is in such wonderful company.
The Museum of America and the Sea at 95 Greenmanville Avenue Mystic CT, 06355 may hold correspondence between Robb and Easticks. I have requested copies of anything available.