SVK
Mixing the Hydraulic Oils is not such a problem (OX 19 for the J by the way) The Aussie J's drained all theirs out and use good old OM15. A brake unit for a J will come filled with OM15, and for example, an Aileron Booster Pack will be tested on the rig with OM15, and then drained and filled with OX 19. So there is no problem with incompatability.
What is more likely to happen is that some tradesmen will use an unfamiliar item of access equipment, incorrect for the task and of uncertain serviceability, and the thing will topple over and three blokes will fall from a height of about 12 feet to the hangar floor.
Gives the hofficers something to do though.
How do you get 12 officers in a Mini. Just mention Accident Report and they'll all disappear up their own @rseholes.