Aermacchi, aka Aeronautica Macchi Manuafacturing Corporation - this Italian name from the past was synonymous with racing success.
Sammy Miller is pictured above. IIRC this was taken at Silverstone in 1995 for the Classic Race Day.
The above bike, in beautiful condition was pictured on the Isle of Man at the 1999 Manx Grand Prix. IIRC it's number plates are from it's entry into the 27th Manx Rally.
If you know the bike or rider please let me know their details, as I didn't get the chance to speak.
1966 Aermacchi M-50.
The above bike is amongst many featured on the below Aermacchi Harley-Davidson site.
American site run by Eric Spurgeon. Includes a for sale/wanted, tech tips and gallery with a wealth of details especially on the bikes built during the 1970's when Aermacchi were working with Harley-Davidson.
http://members.aol.com/italianhd/index.html