Fully understand what you are saying but the smoke alarms and the emergency lights were requested by an outside company who were brought in to advise on the type and position, and in both cases specified equipement of a lower standard than those of which we are installing plus we are installing more lights than the company suggested.Not sure where that comes from but it isn't BS5226:1. Unless you are installing these systems to specification then you must have and be conversant with the relevant standards. Never ceases to amaze me that electricians have BS7671 but assume they can specify and install safety systems with zero knowledge of the relevant standards.
So I'm not concerned about the quality of the fittings that we are installing only as to whether or not there is a reg stating that we can't shut the whole light circuit down when testing the emergency lights. because as stated the test will be carried out at a time so as not to inconvenience the tenants, and just to add this is a 1930's house with 5 tenants not a hotel. so if no one can help us find a reg or come up with a reason why we can't implement the system as I've stated the just purely for the ease of installation and the cost we will put an inline key grid switch in place.