 Complete the following phrase:  However, the rapid evolution of racing machinery, inspired by the rewards offered from the Championship, meant that for Gerard would have to abandon his old ERA in favour of something more modern. Retaining a degree of patriotism, Gerard bought a Cooper T23-Bristol, which he would continue to use for both Championship and non-Championship races until when he upgraded to the new, mid-engined T43 chassis. While he only twice finished in the top ten in Championship races in his Coopers  in 1954 and in his final Championship event at the 