There’s now a build of JHOVE with some more changes, incorporating new code for finding the PDF trailer and making several fixes in PDF-A checking. The full build is a pain to do, so what I’ve done is uploaded a zip file that contains just the revised bin directory.
To use it, make a copy of JHOVE 1.7 (don’t blow away your old one!) and replace the bin directory with the bin directory from the zip file. Please give feedback on any problems encountered; this is definitely not a stable release.