Maybe a bit late on this thread but I worked on the Nimrod MR4 in 1999 when Cobham was refurbishing 3 fuselages.
The airframes had been coccooned in a wood and were rotten, We replaced at least 60% of the structure on one and another was 1 complete frame bay short - lack of parts during the last builds at Chester I suspect.
A good part of the blame for the cost overuns and hence the cancellation of the programme must be laid at the feet of Bae Systems who were in control - and I use that term very loosely. Most of their advisory team were never on site so there were delays after delays. They should also have done a decent survey of the airframes and refused to accept such rotting carcases from the RAF.
The RAF will not be without their share of the blame with constant changes and mods being added on - I worked on the Tucano builds at Shorts and that was a nightmare.
Overall I think the Nimrod (Comet) was a much better plane than the Joint Rivet (707) - my son has worked on both in the RAF - and was better suited to the maritine missions.
Reminds me of Harold Wilson all over again cancelling the TSR2 and buying F111's that were then cancelled with a large penalty paid.
One day goverments will wake up and ask someone who uses the tools what they really need to do a proper job.