This is a 1948 Regal III coach with PRV bodywork for GNRI (the Great Northern Railway of Ireland). 

This is another 1948 Regal III coach with PRV bodywork for the South American market. 

This is a 1949 Regal III coach with PRV bodywork for the Danish State Railways. 

The following are AEC Regal Mk III's dating from the early 1950's (Can anyone add more information?)

 Björn Forslund writes "these images are of the first AEC Regal Mk III chassis imported to Sweden by ANA of Nyköping. The chassis was probably No. 9621E937 dating from 1949.  It was initially demonstrated at a bus exhibition and then provided with bodywork by Hägglunds of Örnsköldsvik. It was run as a demonstrator before it was handed over to Linjebuss for operation in February 1951; remaining in use until 1965.  You can se the 'H' symbol in the front denoting Hägglunds".

Preserved at the Finnish Museum Mobilia (in storage) is this AEC Regal Mk III with Valmet body from 1950 (in service until 1971). To the left is a British Thomson-Houston trolleybus, with Valmet body, from 1949 (in service to 1976, when trolleybus operation ceased in Tampere). Both buses belonging to the traffic company of Tampere. © Björn Forslund

This a 1951 Regal III with PRV bodywork (Body Nos. B34674-88). It was used by Linjebuss of Stockholm as a long distance (international) coach.  Björn Forslund of the Svenska Omnibusföreningen (Swedish Omnibus Association) advises that, during the 1950s, about a hundred AECs were imported to Sweden.  Approximately seventy were pre-built in the UK with PRV bodies and the rest were bodied in Sweden.  The majority (about eighty), including all the PRV bodied buses, went to the Linjebuss company.  However, when Sweden converted to right hand traffic in the autumn of 1967, almost all AECs were scrapped. A few survived for some years converted for other duties and, since the mid 60's, one of them (No. 506) has been "resting" at a former scrap-yard in Varmland, near the Norwegian border; however, after an accident, 506 was rebuilt with a Swedish Arvika body.

This is a 1954 Regal III (Body Nos. B37190-3). One of a batch of four in service with COPSA in Pando, Uruguay.