Quoting: FUBAR
Is that "World Final" in the american sense
Not exactly, the world final grid is made up of 34 cars. Only 20 of those are for UK drivers that have qualified through a series of races throughout the system (this isn't limited to UK drivers either, just anyone who races in the UK series).
12 places are reserved for overseas drivers, who are typically Dutch (they race cars to the same specification), New Zealand (they race very similar, full contact cars), South Africa and USA (Sprint Car/Late Models)
The final 2 places are for on the night, last chance qualifiers and is open to anyone that races that night. There's expected to be over 20 non-UK drivers amongst those that haven't directly qualified.
With £10K up for grabs for the winner, this is usually the toughest and most entertaining race of the year.