There's not a lot of drawing to do with Selly Oak. After all, the railway side is a double-track line with no pointwork. No need to fire up AnyRail for that!
However, the plan involves several different ground levels and the best way, for me at least, to understand that is to build a model of the model.
Using Daler Board, I created the basic baseboard shape and marked it out with 1cm squares representing 6 inches.
The plan involves a pair of 3ft by 2ft baseboards. I can't accommodate anything longer and since this model focusses on model buses, the scene doesn't need to be too long. We can always extend later if more train space is required.
I'm also trying to keep the project sensible. It needs to be completed by the end of November 2020, not take as long as Pendon. With this in mind, the canal is forms the front edge and the massive factory that should be where the viewer is standing is simply ignored. Much as I love an industrial scene, all I have to work with are some aerial shots and very little detail. Besides, there were no buses, so we're not interested.
The main road runs from the front right under the bridge. A side road heads to the station, it's a bit bigger than real life, but would allow more bus parking. The industrial/scruffy area in the middle needs work, but I've left in a pair of branches from the canal that disappeared around the period modelled, but we can't be sure exactly when.
Most of Birmingham will be on the backscene, including the famous university clock tower. First thoughts around this are something impressionistic rather than trying to create a photo. There have been so many changes to the landscape you'd be starting from scratch anyway. More to the point, we want the focus on the model, not the stuff behind the railway.
Why is this V1? Because there's not enough road and bus space. More thinking was required.