... Gulley may be able to explain the intricacies of the track and why there's changeover track in a very small station.
It's what's called a trailing point, once quite common in the past at most double track line stations under the control of a local signal box.
The general idea was it would allow the train or engine to pull just beyond it, then reverse and swap onto the other track to go in the other direction, useful for example in an emergency if the line ahead was blocked.
Often it would also be required to allow convenient shunting and bi-directional wagon movements in and out of a local goods or coal yard if there was one.
I can't find a track diagram for Otterspool so I've no idea if there was a goods siding layout, but if there was it would be behind the camera in the picture.
Since they left nothing nothing to chance and required a signalman to throw them in conjunction with deliberate but controlled engine movements under signalling, trailing points were always regarded as generally being far safer than facing points which a driver could enter at speed and if the signalman had forgotten to reset them, suddenly find himself running on the wrong track in the wrong direction and with possibly disastrous consequences.