A couple of problems were caused by the changes in the IMT 1.5 file format, and I fixed those easily. The rest are caused by the fact that, while previously we were using a simple "docbook_" prefix for all xml:id attributes in the DocBook output, that was changed in the reverse XSLT (producing the Docbook files) to be the xml:id of the document itself (derived from its filename), because our Help documentation works by XIncluding multiple files and all xml:id attributes need to be unique in the combined file.

This is logged as fixed, but I need to do some more rigorous testing to be sure, so I've left the task on outstanding till I've done that.