Q
Your interpretation of the payscales is correct.
New joining FOs start at £23920, rising to £27737 after a year (ie you work diagonally through the table).
Doors, in answer to your question why payscales appear to fall for year two, it is because FOs originally started on c£26000, however last year this starting salary was cut to £23000, rising to £26670 in year 2.
All the best,
FB