Well these things are normally determined on a route by route perspective. There are 3 broad categories here:
Euro short haul: As per VKs note starting this thread, they are pulling out of many routes, not able to compete. Their network is barely a shadow of what it once was. So no competition issues with this
Mid -Haul: As a consequence of no real future short haul, they’ve staked their future on the routes that are ex B-Med, and were only recently flown as BA. Given come of these routes are relatively new I doubt they are making masses of money here. Only Cairo, Tel Aviv and Moscow are in direct competition with BA, most of the others they run code share with BA. I cant see too much competion trouble here
Domestic: this is the trickiest, as Scottish / Manchester customers do need to transfer to LHR. But this is only an issue on 3 routes. BMI are the sole incumbent on the others which BA left many years ago or never operated. So there might be a need to allow a new operator on for competition.
So overall I don’t really see a huge competition case to answer. A few adjustments and concessions should be sufficient on the few routes where BA and BMI actively go after each other.