Beechey, who launched PlymFit with club team-mate David King, ran 21.56 seconds for the half-lap distance.
That beat his 21.68 second PB he had set at Watford last month. It was also six hundredths of a second inside Tyler’s Johnson’s City of Plymouth record.
Also at Newham, Plymouth teenager James Arnott warmed up for the IPC European Athletics Championships in Italy, which get underway on Friday, with an 11.45 second 100m run.
IWAS World under-23 200m champion Arnott, who competes in the T46 category, will be making his senior debut at a major championship in Grosseto.
Among the other athletes competing at Newham on Sunday was Plymouth University’s Jonathan Le Grange, who ran 11.47 seconds for the 100m and 23.61 for the 200m which were both PBs.