[ViridianFan]

The other reason they had to delay the background was because the two screens at the back of the set were mirror images of each other. So if someone walked to the right they'd have bumped into themselves walking to the left on the other screen

I think you’re thinking of the first national studio in the red and cream era. That backdrop was the mirror image which is why they had the column in the middle. I remember when we went on a tour of TVC when I was younger the tour guide told us that there was one occasion when moria was reading the news before being seen going up one stair case then a few moments later seen going up the other. 

The Norwich backdrop was only the single shot of the forum as it was. 

I was always surprised they never had the camera point out the other way to look through the big glass front of the forum which looks out across mancroft church, the market and the castle and cathedral in the back ground. Fingers crossed that’s the view when we get the awful new set install. Poor Norwich never got to get the broadcasting house look