Wrong again, Terriblyboring. The briefing paper on the Bill states quite clearly that the result will be advisory only. It is not within the PM's power to amend it unilaterally, it requires Parliamentary approval.

Cameron took it upon himself to ignore those provisions. The High Court ruled in November that a referendum can only ever be advisory. Therefore it was never within Cameron's (or May's) power to declare it binding. They chose to accept the result, they were not bound by it.