As above.
halfway point and use your meter, before I do anything I look for external devices, eg sounder, call points are my first target.
with only 16 shouldn’t take too long even if you looked at them all.
had to find one on a 120 loop once, took about 6 hours, mixture of old MI and botched in 4 cores ect, real treat it was, traced it to an adjacent private building, he just got a new dog who was chewing an old cable in the porch!!!
the bloke thought it was funny... until he got the bill