I think I can tentatively come to some conclusive statements about this station. It's a little difficult because none of the 25" ordnance surveys prior to 1907 are available. This only leaves the 6" maps, which are not really detailed enough. I now believe the sequence of events to be:
Original 1846 station built on North side of line to the west of the signal box, hence access to this originally on the west side.
Signal box built 1876, with access on west side.
Old station building demolished and replaced by new station house prior to 1892 along with wooden offices, etc. On the North side, approximately on the site of the substation. So further east. A wooden canopy built on the south side without the wooden building.
1892 the wooden building fronting the canopy built facing Station Square (later Devonshire Square).
Most of this was removed when the new 1902 station was being built.
A few intriguing things.... the two windows in the wall, just East of the toilets are carried over from the old station. What purpose did they serve? When was the replacement station built? Guessing 1890 -2, very similar in style to Falmer 1890.