When I ran a flying club several years ago, the policy was that all FIs should instruct PPL topics using the same methods - e.g. 'point-and-power' for the final approach and 'standard closing angle' for visual navigation - and used the standard navigation routes in our training manual. But they were free to use their own style.
A couple of them confused students by using methods which weren't our standard - and inventing navigation routes of their own which weren't in our manual, even though the weather was fine for the standard routes. They were a PITA and were advised of the error of their ways!