Do any of the lights flash a certain amount of times or is it a constant flashing, they should be flashing a certain amount of times in order for a error code to be obtained, which would help understand the nature of the fault.
The fact the issue occurred mid cycle would suggest its likely to be a drain fault, but there could be other reasons to.
This would appear to be a hardware fault, my suggestion before booking an engineer is to switch the machine off at the wall, remove and clean the filter, which will result in removing water from the washer, once you remove the filter have a good look inside the housing to check there is nothing in there causing a blockage, clean the filter then replace it.
Turn the machine back on and see if it goes back to fault mode with the flashing lights, as by draining the water it should get the machine to start back up in an idle state.
If this doesnt work, its time to get an engineer who can strip the unit down and see which component is at fault, if you would like me to recommend someone please provide your post code.
I look forward to hearing from you