You need to stick to a standard frame rates - other wise you could run into compatability problems. Not all players can handle NTSC just as not all players can handle PAL - so whichever you use (and i'd suggest PAL for UK based stuff) there's always gonna be someone unable to use it.
Standard PALshould be plenty fast enough - the standard celluloid film frame rate is 24fps and thats coped fine for decades.
What exactly is going to be on the dvd?