Originally Posted by
corporate-wage-slave
Also check the cash fare for buying, it's relatively inexpensive on that route and you may be able to use your Avios in more fruitful ways.
That's my perception too. I can see not much difference in fare between LHR-LAX and LHR-LAX-HNL (and LHR-LAX-OGG). So if I were you, I'd think for a potentially better use of Avios.
EDIT: by the way, I think the LHR-Hawaii route is one of the best value-for-money routes, when you consider the mileage!