Hi Simon,

It seems to me that your best approach for this is when you capture the footage initally select the option to capture to timeline then if you just need to trim black use the tool on the timeline to trim the ends if you need to take black out the middle i would use the split clip and then trim either side of clip that can be found on the top of the timeline, once you have cleaned the first section simply capture your next section to the timeline and do the same once you have done all your editing go to dvd on the top of the premiere screen and this will allow you to put chapter markers in and set up menu screens.
Then just export to dvd and hey presto you should have a working dvd (well thats how its meant to work)