This is a very well established event, in fact, this year is it's 66th running, and is advertised as the "the largest gathering of veteran and vintage machines in the world".
The 2014 programme shows 550 machines entered, ranging from 1904 to 1930, so the
youngest bike is a mere 84 years old! (and you thought your machine was getting on a bit!!)
http://www.banbury-run.co.uk/Sunday 8th June 2014 at the Heritage Motor Centre, Gaydon, Warks CV35 0BJ
65 acres of parkland 12 miles north of Banbury, Next to M40 J12.