Weekends are always the hardest to crew these sets (given the numbers of staff who don't sign them and the demand for staff to take days off or not work rest days at weekends), so it makes sense they don't usually get used except a few times in the summer when the swap move from Holyhead to Crewe and back to Bangor managed to run with passengers. Also means extra opportunity for maintenance time for the 2 sets not stuck in Holyhead, although that set does often get some clean and prep done at a weekend from what I've seen in the past. Weekends more likely to see more limited diagrams after the Swansea to Manchester turns start in late 2022 as there will need to be big numbers of crew who know them on the Marches end.