Ah yes, DAB and its bit rate changes. I guess you need to experiement with some different command line MP2 decoders until you can find one that can emit clean WAV data for LAME to consume.

As part of your MP2-OGG process you are probably using just such a decoder, unless the OGG tools know how to consume MP2 directly ?
_________________________
Remind me to change my signature to something more interesting someday