Excellent first post chesna152 and welcome to the forum.
The plan was to change the 'numbers' on the runway several nights ago from 06/24 to 05/23 but wet weather has delayed that. Meanwhile the taxiway marker boards had been changed to 05/23 so there was some apparent confusion as to what the ATIS should transmit.
As far as I understand the situation regarding delayed evening arrivals at SEN it has been a matter of the Operations department not being able/not feeling it cost effective to handle them much later than midnight. This year RFF cover was increased to Category 6 so that helped and I believe Operations are now more inclined to ensure that handling is available much later into the early hours. SEN always has been H24 from an ATC point of view so no problem there.