Hi David,
I use C-MUNIPACK (http://c-munipack.sourceforge.net/) for DSLR (and CCD) photometry. The help isn’t very good but it will output to the BAA VSS format. If you process a lot of files (1000+) at once, for example doing a time series of a eclipsing binary minimum, be prepared for it to take a while. On my old laptop it can take a hours, only to find that I need to tweek a setting and start again.
James