Yup, many cutouts and boards have the name of the electricity company cast or engraved into them, and a fair few had isolators. The brand name is Coolex (not Doolex) made by the United Electrical Co. in the 1930s. The design is partially modeled on a 30A switchfuse with the body the 'wrong' way up so that the isolator is above the fuses instead of below. In that era many manufacturers still used the slim case with the bulge over the switch shaft. In time most adopted the flat-fronted case. I have a catalogue listing Coolex switchgear but I can't recall whether it includes heads and cutouts.
As a lot of people have pointed out, we have an interest in these things at the museum and they are hard to pin down at the point where the DNO actually takes them off the wall. Sometimes they get irretrievably broken in the process, sometimes the DNO people won't let them out of their sight because of the possible asbestos content, but occasionally they can be convinced simply to forget to take it, possibly with the aid of beer tokens. If you decide you don't want to make a gadget out of it I would be very keen to convert it back into beer tokens for you and make it part of one of our displays on a mock-up of a vintage electrical installation. I might be persuaded to trade it for a real vintage light switch or something more directly useful. We have a couple of Coolex items already but not DNO gear.