Larry
I assume you will want to run more than one locomotive on the branch at a time which means the signalman will have greater responsibility and will need a clear view of operations. Otherwise, with only one loco (as on the Shipston branch) you wouldn’t need a signal box at all, just a point frame. So I would go with the plan that has no blind spots.
I don’t have my Branch Lines around Oswestry book with me but from what I remember, most stations had their signal box on the platform, assuming operations needed a signal box. In some cases these doubled up as a level crossing box, typically at the end of the platform adjacent to a road, but I digress.
I think it might also be handy to have one or more Whistle boards on the layout!