In reply to DaveR. Daihardwelshman has settled the Penrhyn Service Station. Its still in the same place, its just that the flats were built between it and Penrhyn Avenue so it is hidden. The flats were built on a concrete platform which was the home for Cromwell tanks and Self-propelled guns which were used for training the Gunners before off to North Africa. As to the other site, as far as I know it was never a "garage" as such. It was owned by Pyes coaches in their prime. All the maintenance on all the fleet, which was extensive , was done here and there would have been fuel pumps installed.
Pyes went into serious decline and at some stage they moved the maintenance, such little as there was, up to Princes Drive in the Bay. Presumably the buildings were pulled down and the land sold. There must have been a long period of time between moving out and the flats being built. I don't know what, if anything, went on there during this time.
Just out of interest around 20 years ago the grandson of the "old man" Jonnie Pye showed me a folder of very nice original black and white photos of the Pye empire from immediately after the war period. One he proudly showed was a six in hand stagecoach with all the immaculate horses plus a trumpeter (or whatever they are called) riding up front, the driver, the stagecoach, and Jonnie Pye himself in black top hat and tails standing alongside. Jessie, the grandson, said to me "this was taken in Princes Drive." I looked at it and immediately I knew he was wrong. Clearly in the photo there was a tram standard, quite unmistakable, so it had to be alongside the tram route. I told him, sorry, Jess, I know more about your family than you do. The was taken outside the garage in Penrhyn Avenue. Big laughs all round.