Looks like BA are wet leasing Qatar aircraft...but at least its only for a short time...possibly just to get the ex monarch slots expansion going....
"British Airways Plc applied on 4 December 2017 to wet lease six Qatar registered Airbus A320 aircraft, registrations A7-LAA, A7-LAB, A7-LAC, A7-LAD, A7-LAE, and A7-LAF, between 9 February and 9 April 2017 inclusive.
The application has been made on the grounds that the lease is justified on the basis of exceptional needs (Article 13(3)(b)(i) of Regulation (EC) No 1008/2008) to enable British Airways to support passenger operations due to late delivery of aircraft."
http://publicapps.caa.co.uk/docs/33/2258.pdf