Hi Jim
I can't let your comment "the first Burns London production electric" go unchallenged! The Sonic may be a contemporary of the Vibra-Artist, but both were preceded by the Artist which, although only produced in small quantities, was nevertheless a 'production' guitar in Burns terms. The prototype Artist (P.53 of 'The Burns Book') is dated as 1959 and my very early model (with its 'reversed' colour scheme, seen here in its 'untouched' state in about 1964) is also possibly 1959 (source - letter from Phil Sweet/Storm, Jim Burns' right-hand man). The Artist model continued for a time in 1960 until Jim Burns had designed his first tremolo unit, which was then fited to the new Vibra-Artist and Sonic ranges.
Ray
(keen-eyed viewers are no doubt saying "why is there what looks like a tremolo on your guitar, Ray?") The answer is that the Bigsby was already fitted when I bought the guitar in 1963. As the standard Artist had no tremolo it was probably fitted as a special order.