The Allisons scored an international hit with their U.K. Eurovision entry Are You Sure (2nd place in 1961)
Golden Oldie Are You Sure is one of the songs I knew by heart (although in my own invented variation on English) long before I found out it actually was a Eurovision tune.
The Allisons Brian 'John Allison' Alford and Colin 'Bob Allison' Day were childhood friends, not really brothers contrary to popular belief. They were more or less the U.K.'s answer to the Everly Brothers. They scored a European hit with their Eurovision runner up, the third U.K. entry in a row to finish 2nd.
The song sold over a million copies in the U.K. alone.
'Goodbye, Farewell.... Are You Sure?' they asked themselves. I guess they weren't, as the Allisons reunited on several occasions and in the 70's recruited some new brothers like Mike Allison and Tony Allison.
John White, earlier member who left in 1959 is the real composer of their Eurovision Song. (it's credited to The Allisons).
Colin Day also recorded a coverversion of Angelique, the Danish 1961 entry by Dario Campeotto. It was released as a b-side to his single Brasil (Parlophone R 4803).
Source: BBC entertainment
Parts of the above have been published the 2008 Eurocovers article Team GB 1961: Are You Sure?
Discography: Colin Day and the Allisons at 45Cat,com
Another post: Jody Wayne (South Africa) - Are You Sure