Maseratis and ERA

I took this photograph at Luffield corner during the Chopard HGPCA 100 Mile Grand Prix Car Race at the Coys International Historic Festival meeting at Silverstone in July 1994.

Leading is Thomas Bscher's 1957 Maserati 250F V12, a car built with a 2,491cc V12 engine instead of the 250F's usual 6-cylinder inline 2,490 unit. It's chassis #2531 and is one of only 2 cars specifically built to take the V12 engine. The car at the rear is Jeffrey Pattinson's 1954 Maserati 250F, chassis #2508, originally owned and raced by Stirling Moss. The blue car appears to have a number 33 which was an ERA  driven by Duncan Ricketts, and although the programme of the event doesn't identify the four ERAs that appeared in this race, it appears to be R12B. The green car in the background is David Baldock's 1938/39 Alta which was driven by Paul Jaye.