car came into the garage from another workshop having had the battery changed twice by Halfords. alternator changed via another workshop using a an rtx replacement unit from euro car parts. car failed again after two weeks usage. car was towed to us via the rac which said that the alternator was not giving out enough output for the type of vehicle, when checked only giving out 12.3v.on testing removed sensing wire from alternator,after that we checked the voltage coming out of the battery which was 14.5v. after this process we changed the alternator with Peugeot approved unit, after fitting new unit the charging was still not correct only 12.3v, small wire removed 14.5v coming from battery. no fault codes in ecm, only error code is in the bsi u1b1f lin fault 21. checked wiring from alternator to ecm and is signalling,no stop start or battery sensing device. any suggestions