While I do not believe LGW has 'stole' the MAN extra flights (CX will up gauge MAN regardless of what they do at LGW), it is interesting that the days of operation are exactly the same as proposed extra flights from MAN.
MAN was due to be double daily on Monday, with Wed, Fri and sun added to make full daily flights, and of course the A350 was due to be used.
All will depend on what CX want to do with MAN. They are apparently reluctant to remove the B777 off the flights due to cargo, as it was originally suggested MAN would go full daily with the A350 on all flights.