Arriva and ASLEF had an agreement to end the dispute, formalities for a pay deal were about to be completed with signatures from both sides when a change to how engineering work and special working hours was sneaked in by ATW.
The maximum day for short term plan (STP) for engineering work or special working could extend your day to 11.5hrs. Those hours for TOCs are especially rare and have been negotiated out of various agreements through past years of fatigue and planning activities away from work reasons. I can guarantee that the 'clause' in question would get abused by rostering staff when there is a shortage of drivers. It impacts a work life balance for drivers by taking you off a booked job and then extending it by enforcing overtime.
LTP - Long term planning diagram - duration until the next timetable change
STP - Short term planning for whatever reason a company feels that and STP is required, it could even be a 1m later departure on one train at one station with over 80 station stops on the diagram.
There is a huge difference between the 2 types of diagram.
For instance, I get STP diagrams on a frequent basis possibly every other day.
So, if a promise is made for a maximum turn length that takes a few years to finalise that should be the maximum turn length whether it is LTP or STP.
Now if there are special events or engineering work that are clearly going to extend diagrams then yes, possibly a longer diagram could be accepted for this scenario but such scenario needs to be set out with any agreements.
This may explain the difference between LTP and STP diagrams.