Good progress so far.
I have mixed feelings about a clear coat over metal finishes, as, depending on the type of paint used, the clear coat can often enhance the metallic particles in the paint, giving a "grainy" appearance. However, I do normally apply a thin, brushed coat of clear over the decals, to prevent them chipping/cracking/lifting on bare metal.
BTW, it should be English Electric Lightning, not British.
English Electric was the name of the manufacturing company (who also made fridges !!), and later became part of BAC (British Aircraft Corporation, now BAe ) after a merger and nationalsation of the British aircraft industry.