I see this kind of thing all the time.

Car is brought in after RAC/AA/Green flag/A.N other recovery service has looked at it..

Fault report reads as above 'module lock up,battery reset blah blah'

Trouble is, they usually clear any fault codes in the system which could usually point 'me' to the original fault.

So until the car faults whilst it's with 'me' I'm looking at it blind, and with these things it could be absolutely anything, so not as easy as replacing a relay as a guess or whatever.