> "Is there a designated gathering place?"

Mark, up on the hill of GDSF is the Organ Alley.  See their web site,
http://www.organalley.co.uk/  This could be a perfect meeting point!

Hiddo van Os

 [ At http://www.organalley.co.uk/ : "Organ Alley is a section of
 [ the Great Dorset Steam Fair (GDSF), where you will find a group
 [ of enthusiastic organ owners keen to share their enthusiasm with
 [ one and all!"  -- Robbie