Are you sure they were vine weevil larvae and not chafer grubs, or even (less likely) leatherjacket larvae? Vine weevil larvae tend to inhabit pots first, then borders where plants are growing, rather than under grass, so its likely, if they were vine weevil larvae, they won't be a problem underneath turf. However, if they were actually chafer or leatherjackets, that's a different matter - they love being in grass. There are treatments available, but its important to decide precisely which larvae you've seen in order to select the right treatment, or even to decide if its necessary.

Vine weasels? I know you mean weevils.

The most effective treatment is Nemasys, a nematode preparation. Their life cycle means that there are few larvae now, they are all emerging as adults which are relatively harmless. But they will lay eggs in the summer and larvae hatch in the early autumn. The best time to treat is September to kill the grubs.
Similar Nemasys nematode systems are available for both leather jackets and chafer grubs.
Avoid insecticides as they will kill the predators of these pests as well.

http://www.nemasysinfo.com/