After my mothers house was rewired some of the old wiring was reconnected using a fuse as shown
and the supply from that actually powered sockets in the next room as well as the room with the fuse. In the kitchen, not a clue why my dad had a FCU feeding another FCU, and in last house the old immersion heater feed was reused, so one socket in kitchen where old switch was, one back to back of that socket in the living room, and one in the room which had originally had the water tank in.
So the fuse protecting the failed sockets may not be where one expects to find it. Since I have a non contact voltage tester that's what I use,
seen here showing a supply to multi socket, I am sure one can use a bulb and two wires, but safer to use some thing designed for the job, to swap a fuse you need to double test, put the old fuse in some thing to see if it still works, and well as fitting a replacement.
But without tools one must except testing is limited, not saying you can't test, plugging in a desk lamp is a form of testing, but without the tools testing is harder, how did you know the fuse you fitted was a good fuse for example.