if the same instructor thing is true then it is indeed against the CAA rules. The examiner, where possible, conducting the LPC/OPC should not have been involved in the candidates training.
Respectfully suggest this really only applies to an LST rather than LPC. See extract from CAA Doc 24 with particular emphasis on the word rating. One is not normally given training for a rating renewal and I assume no new rating applicable in this case? But like many things can be read to be a little ambiguous.
3.8 JAR-FCL states that “Examiners shall not test applicants to whom flight instruction has been given by them for that licence or instrument rating except with the express consent in writing of the Authority”.