Spinnaker,
The Airframe manuals simply refer you to the Lycoming ones for overspeeding, which indeed gives the allowances, the fax from the manufacturer of the Engine confirmed these and that it was alright and that was passed around for all to see.
Though you say did I make every manual available to them, then the answer to that would be no, those that requested to see it I offered to show them if they popped over to the hangar, though even that some could not understand to be honest, at some point you have to trust what the Licenced Engineer who is doing the job and clearing it is telling you, exactly as a Captain has to trust the Co-pilot sitting beside him or the hostess down the back.... I can and would be happy with entries put in if something had changed in the original percieved fault, but when they are simply snagging the same thing for the same snag, then that is just being bloody minded.
The reasoning I additionally spoke to the CAA surveyor as I wanted to clarify the position in that the Aircraft Type Data Certificate for the Aircraft gives the max Engine RPM's there, even though this particular aircraft was slightly exceeding those and the Engine manufactures manuals allowed the Engine to exceed these, the Type Cert relates to the Aircraft limitations, I wanted to clear it in my mind that this was acceptable as that was new waters for me and I wanted to be 100% sure on it.