The three 1953 references clearly state that Pretoria won a certificate of merit; in particular in Rosenjahrbuch and in American rose annual it is clearly stated that it won a second certificate. In particular the report in American rose annual was signed by Countess Mary Senni who lived in Rome and ... was "on the spot". According to two references, the winner of the Gold medal at the International Rose Trials of Rome in 1953 was Pastorella by Meilland.
Sheenagh Harris apparently has quoted Modern Roses, which has it wrong. As Cà Berta says, contemporary publications clearly state 2nd Certificate of Merit.
According to two references, the winner of the Gold medal at the International Rose Trials of Rome in 1953 was Pastorella by Meilland (see the missing rose Pastorella)