right middle – #34 Aston Martin DB4GT but not a Zagato
left middle – Whitmore Mini / #30 Austin Healey 3000 / Lotus F Junior
lower down above picnic – #17 is Jack Brabham’s 2.7-litre Cooper-Climax raced at Indianapolis in 1961 and demonstrated here at Silverstone
bottom left #33 is Whitehead’s Ferrari 250GT
right middle – #34 Aston Martin DB4GT but not a Zagato
left middle – Whitmore Mini / #30 Austin Healey 3000 / Lotus F Junior
lower down above picnic – #17 is Jack Brabham’s 2.7-litre Cooper-Climax raced at Indianapolis in 1961 and demonstrated here at Silverstone
bottom left #33 is Whitehead’s Ferrari 250GT
Updated, thank you!