Wonder if they're going to reseat some of the vehicles to standard class. I seem to recall that the 7-cars are somewhat over provisioned at the moment due to their history of originally being 9-car sets. So reducing a pair of them to 5-car would potentially make that worse!
I suspect they would because the aim of strengthening the 4-cars is surely to give them two unit formations for diagram purposes instead of three, including two seating capacities/layouts to also simplify reservations.
It also depends if they look to reduce First Class provision in the remaining four seven car units. This could be done by removing a Motor First (MF) and a Motor Standard (MS) from 222001-222006, and reconfiguring the remaining MF as a Motor Composite (MC).
They could then convert two of the removed MFs to MSs, and have four MFs and eights MSs to strengthen 222101-222104 to seven cars.
This would simplify things as the 23 222/0s would all be 5-cars and the four 222/1s 7-cars.
Just making the 222/1s 5-car still needs two MFs converted to MSs before being added, plus the existing four MCs First Class provision doubled, as well as two MFs converted to MCs in the two new 5-car 222/0s.
In either of my suggestions you have to reconfigure eight coaches.
