DOT means 'Devoid Of Trouble'
Desmo you started riding in 1966 and started racing this year! You are really something
I was born in 1967 and started riding in 1982, but my momentum was slightly reduced in 1985 when I got a 30cm blade and 12 screws to support my right leg, very stupid crash and it was my fault
It was even more stupid that I started riding the bike and even rode from Athens to Paris through Italy while still using crutches to walk
I 'm younger than you, but I really like motorcycle history and old bikes.
The Greeves, Cotton and DOT were respectable brands, but relatively small scale manufacturers who preferred to concetrate on the cycle parts and use a proven motor like the Villiers.
The Villiers engines were very popular at the time (something like the Minarelli engines were in Italy later) and they werte used for both off- road and roadsters as well as racing.
They were used also by Panther, James, Francis Barnett and others that I don't remember now.