OK, cheers for getting back to me Craig.
I have managed to achieve a high quality result overnight, here’s what I did:
FCPX – Share>Send to Compressor – Setting Apple>ProRes 422. Imported the Chapter List .txt file and submitted. It created a 114GB .mov file which I thought would be a problem, but I simply imported that into iDVD and the chapters came through with it.
Changed the iDVD settings to Dual Layer and encoding Best and off it went.
The results were the best I’ve seen in the week or so I’ve been fiddling. And although the iDVD menus aren’t as nice as DVDSP, at least I have a suitable product.
I think previously I was using compressor/FCPX to get a MPEG-2 file which iDVD/Toast/DVDSP would then compress to MPEG-2 all over again.
Pro Res is obviously the best way to get the film into a suitable file for these programs to recognise without losing any quality.
Seems quite obvious now, but I really struggled to find this process anywhere.
Anyway thanks for your help and I hope others find this useful.
iMac 2.7GHz Intel Core i5, 27″, 16GB DDR3, 10.7.1, FCPX