When the aircraft was totally and completely rebuilt in climate controlled conditions at Berwick. The woodworker was a professional..
The airframe timbers were totally replaced and all new timber used, many months spent shaping various timbers for complex curves.
I think at the time 99% of the aircraft was replaced. Modern glue, customs jigs,etc. Apart from metal attachment fittings, engine cowling, and the 'data plate' the aircraft was in fact brand new.
Magnificent restoration.