There was a picture of the T antenna between the two chimneys in one of the free radio publications at the time as Capital was effectively jamming Veronica in the SE. I did pass Lots road on a train from Kensington Olympia in the sometime in the eighties when Radio 4 were using it on 720 and had a view of the sloper from one of the chimneys. I spoke with a BBC engineer at the time who told me that they'd changed from the T as the sloper worked better.