There was no need to pass legislation for advance stop lines, as the existing legislation already covered them.
A stop line is a stop line, and you MUST NOT, pass over a stop line when there is a red light. So a motorist (or mororcyclist) approaching traffic lights with an advance stop line MUST stop at the first stop line that they reach.
So if they have not passed the first (the advance) stop line when the lights go red, then they MUST stop before going over the (advance) stop line into the cycle box. If they have already passed over the (advance) stop line but have not fully passed over the second stop line, then they MUST stop and not pass over the second line, so can legally end up in the cycle box.
A cyclist doesn’t pass over the advance stop line, because there should be a cycle only lane on the left which doesn’t have a stop line, so they can enter the box legally, and then wait at the second line.
So no legislation is needed, just enforcement.