Hi RST,
No offence taken, I should have checked Google more closely however initially most of the photos I found were of the Pilipino navy vessels and the ones transferred to the Irish navy, the pennant numbers on these vessels are entirely different from RN pennants. After further research I did find several pictures that do show the white outlined numbers on the RN Hong Kong vessels, some early pictures were not clear enough to see the outline but thanks to Gingyer, who confirmed they did have the feature, I now know this to be correct. This forum is a very useful tool for researching details about all sorts of things, there might well be information out there which is readily available but having experts out there ready to help and to point a researcher in the right direction is much appreciated.
Kind regards 17-09 Alan