My wife has travelled BNE-MEL-SIN-LHR-CPH in Business Class to seek treatment in Denmark for spinal cancer. Our 17 year old daughter travelled as her assistant, also in Business Class. Special assistance (wheelchair transfers) was included in the reservation. The trip was a nightmare !!

Check-in in Brisbane got the journey off badly.
(1) Online seat selection was never available for the MEL-LHR trip, the screen would say "Seat choice will be available at check-in" or on the Qantas website "advance seat selection is not available for this flight, please select seats at check-in". So my wife, with very limited mobility and considerable pain on standing and walking, was unable to do seat selection to pre-select seats alongside our daughter with easy aisle access and as close as possible to rest rooms, etc.
(2) Online check-in for BNE-MEL and MEL-LHR-CPH was never offered either under BA's Manage My Booking or her Qantas login. The BA website stated "check-in via the operating airlines website" but on the Qantas website the Online Check-in button just did not appear. So my wife was unable to check-in prior to arrival at BNE domestic, and unable to go directly to bag-drop.
(3) Upon arrival at BNE domestic we found that assisted check-in counters no longer exist, and the electronic check-in would not check my wife and daughter in either. In great pain my wife made her way to a person at the far left of the check-in area, only to be told that she had to go to a counter at the far right of check-in. By now she was in agony.
(4) Despite having Special Assistance (wheel chair, etc) in her booking, to this point we had still been unable to find a "human" to provide this special assistance.
(5) Not surprisingly at check-in the remaining seat selection options were limited. Despite the Special Assistance annotation in the booking, the counter attendant initially just gave my wife and daughter the first seats offered for MEL-LHR. These were several rows away from the rest rooms. Only after I firmly pressed the point were some seats nearer the rest rooms offered.
(6) Only after check-in was complete was the wheelchair fetched for my wife, who by this time was sucking on an "Actiq" opiate painkiller stick after having been standing and walking for over 20 minutes. The painkiller had been reserved for the time that she would have to sit upright prior to, during and after take-off.
(7) My wife finally boarded the BNE-MEL flight in extreme agony. A very distressing start to a 33 hour journey. We had really hoped that she could have at least made it on to her first leg in a relatively comfortable state. BA/Qantas certainly ensured this was IMPOSSIBLE.

Transfers were reasonably smooth thereafter through to Heathrow. By this time my wife was exhausted (30 hours travel) and in much pain. Now the saga started all over again:
(1)Flight BA 7309 arrived into Heathrow 45 minutes late at 5:45am and my wife had to wait for 3 wheelchair interchanges, and ended up missing the connection to CPH by 5 minute. Each time they changed over wheelchair and driver they lost about 10 minutes.
(2) Flight BA 0812 took off from the furtherest terminal at Gate 48. When they went through security screening it came up that boarding had closed and that was at 6:35am for a 6:55am flight. The desk attendant agreed to hold it open if my wife and daughter could go straight there, but from there on they had to go up and down elevators, onto a train and through security screening a second time (taking shoes on and off). They got there at 6:50am (5 minutes ahead of scheduled departure) to be told "too late", the flight doors were closed and our bag had been removed. My wife was shattered.
(3) They were taken to the BA Club and were told that they would try and get them on the next flight at 9:20am, but it was pretty full and Business Class may not be available. It was now 7:05am. My wife advised that she would not make it until the 12'ish flight which had spaces as she would need to access furher painkilling medications by then. BA then offered that my wife fly Business Class and our daughter go Economy. My wife cannot get in and out of her seat without our daughter's assistance and stated that our daughter was her helper and she needed her in the adjacent seat.
(4) By the time they finished at the desk it was 7:30am and BA suggested that they go back to Terminal 5, but to A as there was a lounge that was closer to the next flight departure gate. BA also arranged for their suitcase to be held airside so that my wife could get some extra pain killer. They didn't get back to the A section until just after 8am (2-1/4 hours after landing) at LHR. My daughter had to buy water for my wife during all the messing about (clearly "Z" class rather than Business Class).
(5) Next the wheelchair person got lost, and from having 3 hours they had just 15 minutes in the lounge.
(6) At the lounge counter they got my 17 year old daughter to sign something (remember this is my wife's booking that my under-18 daughter has no right to sign for) and they gave her a paltry 30 pound credit voucher for surrendering her LHR-CPH Business Class seat (and the price difference on the BA website is 322 pounds, plus BA would know that living in Brisbane the credit voucher will never get used, so the downgrade to Economy was effectively not compensated at all).
(7) Once on the aircraft no help whatsoever was offered between LHR and CPH, my wife had to shout down the aisle to economy when she needed my daughter's help.

Terrible, inexcusable, woeful treatment for long haul business class passengers. I wouldn't condemn my worst enemy to travelling with BA.