It is entirely possible that there is no fault with the electrics, a ceiling rose could be wired with no permanent live, even if it has a permanent live, the switched live is normally on the outside of the rose.
Any water creeping into the rose is likely to contact the switched live far before the permanent live. Tracking back through the wet woodwork in the house until it finds a path to earth.
If there is an rcd supplying the circuit, the path to earth through the timber and back to earth via multiple paths is going to trip the rcd well before any risk of shock occurs.
The simple fact is, the system installed because of its age is unable to detect the type of fault that occurred.
Modern rcd’s Or rcbo’s would have turned off the power, probably before the shock risk was there, but certainly the moment a shock was felt the power would be switched off as the device would trip in less than 0.03 seconds (less than a blink of an eye to the layman)