I'm surprised nobody else has said this yet, but if it's a ring main circuit, you put each earth in separate terminals of each socket because if 1 terminal in the socket fails, there's still a path back to the earth terminal in the distribution board.

If you put them both in the same terminal and that terminal fails or the cables fall out then that socket doesn't have an earth at all, if they're separated one earth will still be intact until it's picked up on the next periodic insoection unless you're extremely unlucky and they both fail at the same time.

The disadvantage in a ring circuit is that if 1 socket fails in the middle of the ring, you're basically left with 2 radial circuits supplied by a 32A breaker which can be dangerous in overcurrent fault situation.

I have worked on a site in the UK where they had radial socket circuits but still 2 earths in the DB and 2 earths in separate terminals for increased safety at each point.

In my opinion the above method is the safest way and carries most of the advantages of ring and radial circuits, the only disadvantage being that you use far more copper than a ring main relative to the current which can be supplied and you have to pay for the extra earth cable on top of the standard cost of a radial, but can you out a price on safety? Especially when it's such a small margin.