I understand the theme and I think I know what needs to be rebuilt, but not the replacement elsewhere. Gentle hints on the latter appreciated - I have an idea but it seems ambiguous and these things are usually conclusive.
Am also baffled by the "nominal replacement" to be made ....any gentle hints would be welcomed !! Have otherwise enjoyed solving this particular puzzle.
Just butting in to a thread that goes over my head to say "Love your moniker, lavengro". The Scholar Gypsy and also one of the all-time great Guardian compilers!