Nat West offer an account, which Rewards you with 3% cash back on your household bills paid via DD, but pays zero interest on any credit in the account.
OVO the energy supplier pay 3% on any surplus you pay via DD towards your energy bill, up to a maximum of 12x your DD value. So it seems a better interest rate than most banks offer, so it really is worth while paying too much on the DD to be in surplus.
It strikes me that the larger the OVO DD, the more I get from the Nat West as a 3% Reward plus the surplus I pay OVO also gains 3% interest too. How easy is it to get your surplus funds back from OVO?
What have I missed? Any gotchas?