On page 247 of the first edition of the "Bible" states, "The work had to be carried out at sea but riggers would not come out so it was done by a small group of engineers and djs', Norman, Peter, Dick and Robin.

Whereas the softback states on page 252, "The work had to be undertaken at sea and a team of professional riggers were used" but ultimately after an incident left the Caroline guys to finish the job.

I tend to go with Bob Noakes' version in Last of the Pirates which aligns with my original post, ie the mast was built at sea by Norman, Robin etc.