I accept that there could have been another component failure other than what has been replaced. As a fellow mechanic (Simon) you must agree that the recent repairs are still the most likely cause of this failure.
In the first instance, I would be very keen to pin point the fault , which really shouldn't be too dificult to trace as brake fluid leaks are fairly easy to detect (put the van on ramps and have someone apply the brakes hard whilst carrying out a thorough visual inspection)
Once you know what you are dealing with you can decide on your next move.
If it clearly is poor workmanship, I stand by my first post.
