Had a similar problem, though not electrical with a vintage airframe a few years back and recall well the heated debate that raged on for weeks about using original parts no longer available and hideously expensive too have reproduced against acceptable readily available modern materials.
The anoraks would have the plane reduced to static display rather than give ground in an effort too maintain as they saw it ‘Continuity of Originality’ as one of them put it while the engineers argued that the goal was too fly the thing and not just stand and gawk at it.
In the end it comes down too the original mandate to commence work, ‘To Fly or Not to Fly’ ect and as a result all efforts should be made to obtain and use original parts but in the event that such parts are no longer available through lack of supply or cost of manufacture then alternatives should be sourced and systems modified accordingly to use such parts.
In our case we won the day on this argument alone and modifications too the control runs were made too incorporate modern material pulleys and guides as a result reducing maintenance cost for the future life of the airframe without altering the external visuals of the aircraft which in the end is the view that the vast majority will ever have of any airframe.
In your case the fact that suitable original fuses are no longer available and modern alternatives are it’s a no brainer really, mod the panels, fit modern fuses, inspect it, write up the logs and fly the thing.