Thanks - @clubman, you can only find out if a deed is registered at the land registry, unfortunately, not the contents of the deed.
@eitheangela - I don't think - in fact I'm fairly certain - that we didn't get copies of any other contracts or deeds when we bought/sold before twice. We do have a copy of the contracts that we signed (although solicitor can not find them even though she signed for them). We didn't take a copy of the deed of sale when we signed it in the solicitors office. Should have, but didn't.
It's not the title deeds we are looking for, but the final document we signed which I think was the deed of sale, which has the house sale price on it that we are looking for.