Who holds the deposit money between exchange and completion

[NoseyNooNoo]

We may be buying a house and vendor wants a 2 month gap between exchange and completion.

Who will hold the 10% deposit during this time (and earn the interest). In the account is currently sat in it would earn £600 during that time. Who gets to pocket that?

If it's not us can we do anything about it?

You would pay the deposit to your solicitor who is obliged to pay you interest.
If its a large amount and you know exactly when the completion will be make sure that the solicitor gets the best rate of interest that's available. If you know of a particularly good account suggest it to them as they may bank at the same place (they won't be able to use a new bank just for you) but definitely make sure you know what they are doing with your money.

Thank you for that.

Isn't it held in the Solicitor's client account - which doesn't belong to the Solicitor, so if they get into difficulty, the money is ring-fenced?