Many thanks to Free at Last and 31A for the useful photos and to LMS2968 and Bulleidnutter for the info.
It seems we were wrong to think that UK t/t didn’t have overhead electricity supply - the helpful photos evidence that they certainly did! (You learn something new all the time.)
Our model is based on the SR Ewer Street Depot prototype in S.London but photos of that are, to say the least, elusive, and inadequate to see the drive/ elec supply. I’ve got several aerial pix in the period we are modelling (1951) but they are from too great an altitude to get much detail. I’ll look at them again now I know that overhead supply was used in UK.
But if anyone does have even glimpses of Ewer Street Depot turntable in steam days it would be well received. We have the well known wartime photo of a Schools class running onto the t/t but this is only a partial shot so doesn’t show the full story.
Chris McCarthy