Kieran, I found a lovely freeware utility called EasyBmp2Avi its a command line utility which converts a numbered sequence of bmp files to avi. It works very well. I used it to compile an animation of 2006VV2 a while back.
Just save all the outputs as sequentially numbered files in a folder and then run the program. See the caccompanying usage file for how thats done.
download from here;
easybmptoavi.sourceforge.net/
(get the win32 binary at the end of the download page)
  