Diamonds on Wheels
Both plates are 1960-61 series. Triumph 532PPL is still with us and is a 650cc bike . Previously listed as Tiger 110 but some doubt as Police much more likely to have Thunderbird see- /v001071918.html /vehicle_427208-Triumph-Tiger-110-1960.html Avengers 5.24- T110 would have a bright alloy head, ^ looks like black painted cast iron to me. 6T Thunderbird.
Also /v036542.html , /vehicle.php?id=661813