A chap named Victor F Bingham wrote a book 'Handley Page Hastings and Hermes. ISBN 1 870384 63 6
In the back is the fate of all the Hastings and the entry for TG 507 reads;
'EFS; 47; 202; 24-36; 242 OCU; MoA; To Handley Page for special camera installation. RAF Wyton for special trials'.
SOC 23.4.69