It specifically refers to “filter lane” type signals. It clearly states that a driver may proceed beyond the stop line in the direction indicted by the arrow. This is what the OP did and I believe no offence has been committed.
Logically (dangerous word in statutory interpretation), for it to be otherwise, the traffic lights would need to be considered as 2 separate systems controlling separate junctions. From the GSV link, it is clear that it is a single set of lights.
edit: For the sake of sanity, it should be noted that the right turn arrow does not have the word "Only" painted under it, and therefore is not mandatory