Tubby - I think that constraint only applies to engine-out (EO) operations. When the FMGC detects an EO condition, the AP & FD limits bank angles for t/o & app to 15° when the a/c speed < maneuvering speed (F,S or Green Dot speed) –10 kt. Then it has a linear increase to 25° up to maneuvering speed -3 kt. I hope that makes sense.
Regarding the manoeuvring speed limit, different companies often impose higher limits. The problem comes with definitions. FCOM PRO SUP 10 has some good stuff on this. On conventional aircraft, VA (known as design manoeuvring speed) is the speed above which it is unwise to make full application of any single flight control (or "pull to the stops") as it may generate a force greater than the aircraft's structural limitations. Clearly that is not possible on the Airbus. Therefore Airbus define VA: Maximum design manoeuvring speed. This corresponds to the maximum structural speed permitted for full control deflection, if alternate or direct law is active. In other words, it is not really relevant in normal law. Therefore Airbus talk of 'characteristic speeds' (F, S & O). They also say, the A318, A319, A320, and A321 have exactly the same manoeuvre margin that a conventional aircraft would have at its reference speeds. My own company, however, imposes the limit that we are not to fly below reference speeds to ensure an extra margin of safety. You can argue the ins and outs of that, but that is the 'official' view of many operators. I hope that is helpful.