Rich,
16 tons! It may be that you have something very precious. Amendment sequences for a particular drawing number. In general, only single versions of any drawing number are preserved. A single drawing preserved, D.1649 for example, maybe the end result of 20 or so different amendments, each as a drawing having been issued under the same drawing number D.1649 but with different dates and where all except the last have been discarded.

To have the whole time sequence of the amended drawings for, say, the interaction of the transport joint, former 6, with the front spar would be a Godsend. This is probably the most complex part of the whole Lancaster design. Studying the sequence in order of time would give a real opportunity to be aware of & to understand the various design decisions made in the course of development.
Mike