Thanks all, Lots to think about here!
That's very interesting. It would definitely help to open the goods yard up a bit and I could also move the weighbridge off-scene. Another option is to consume more of the meadow, thus giving access to the southern siding from both sides. But I need to be wary of railway vs. non-railway balance.
A nearby racecourse is a great idea - a great reason for increased traffic in this imagined world. Unfortunately a 45ft table isn't big enough to accommodate most tender locos, although I gather that it was possible to temporarily extend them when required (probably impossible to model). To be honest, I think the writing's on the wall for the turntable.
Two reasons for the crossover at the end of the platform: 1. The southern extension serves the cattle pens, like Moretonhampstead. 2. I think I read somewhere that Board of Trade rules said that where double lines terminated they must be aligned, not staggered. (I must admit that doesn't seem quite right or necessarily applicable in this case, now that I write it down, but I'll say it anyway and see if any experts have an opinion on that.)
[Edit: The crossover at the end of the platform was common to many broad gauge termini, I think.]
For some reason, having part of the station trackwork being implied, off-scene, feels wrong to me. Not sure why. But I take your point about using the traverser more creatively. (I had a secret connection through the engine shed in the back of my mind.)
The closer the gasworks line is to the running lines, the less reason for a separate bridge. But then maybe, with the turntable gone, the whole station throat could cross an enlarged brook or small river on a timber platform. That would be quite a feature!
Decisions, decisions...