Security Roller shutters do they require a special by law

We live in a small apartment block of 7. We recently have had several attempts at break ins. As a result we have decided to install security roller shutters on our windows to improve security and prevent intruders entering. There are other units in surrounding blocks which have these types of security roller shutters. I requested that it be an agenda item at our AGM. I only wanted to inform the other owners that we were going to have them installed. I advised that the shutters would be the same colour and materials as existing security screens on the other units in our block. The owners at the meeting agreed however, the strata manager said we could not install them as I had to have a by law drafted and the by law had to be approved and registered before the installation could take place. I pointed out to the agent that it was complying with by law 5 that allowed us to install safety and security devices and that with permission from the other owners we were not breaching common property by laws. Since the owners already agreed we were not breaching any by laws. The strata manager said we were breaching the by law relating the changing the appearance of the lot and therefore had to have a special by law drafted and approved. The other units already have security screens on their windows, we do not have any security screens so I don't see how this is changing the appearance as our unit is already different in appearance. Furthermore, we will be using aluminum shutters the same colour and material as the existing windows and other units security screens. Do we really need a by law for this as the other unit owners in adjacent blocks do not have special by laws for this. I called OFT several times and get a different answer each time. I want the right answer so I know what to do.