So, does this mean the cabinet is still the source of the problem?
Could it be that the pipework to the tap is not bonded to earth?
Also by holding the probes just between my hands give a 0 reading and the meter isn't picking anything up just from the air.
Or as was originally suggested ( by yourself?) is this all down to the leakage from the cabinet under permissible levels? I still want to get rid of it!