I fly LHS for a major charter airline. I have spent most of the winter flying with other Captains because:
a. We do not have enough F/O's per se
b. We have allowed some F/O's to fly with other operators to save costs over the winter
c. Some F/O's have taken part-paid additional leave - again a cost saving measure.
It is not a major problem in itself - our SOP's work well and I fly from a small friendly base. However, there are inevitably problems with regard to cabin crew and handling agents who don't quite know who's in charge. More importantly however, mistakes are made due to endlessly swapping seats - invariably only minor things but the day will come.............
For reference the CAA have decided that a single engine circuit, single engine go-round and single engined landing in the sim every six months will prove our expertise in the rhs with the recent addition of a LVP approach.