It sounds very similar to my setup, with a meter and a 100 amp fuse set in box on an outside wall. The ohme installer managed to get everything set up inside the meter box without touching the inside fuse board and a very neat job he did too. I had to pay a extra £250 for additional cable length to where I parked and needed the charger.
your setup might be different and only your installer would be able to advise you.