Sorry, wrong number
I very much enjoyed your Lola track tests, but must also 'commend' you for your imaginative explanation of the 1962 GP Lola's chassis number.
BR stands for Bromley (where the cars were made) not Bowmaker Racing. The GP part was correct, but 42 is not Mark 4, chassis 2, as you suggested. Simply, its stands for chassis number 42 in the sequence of Lola single-seater chassis numbers. These, naturally enough, started at 1 and ended at 55.
I am, Yours etc, Duncan Rabagliati, London