In January, our Landlord informed us that he was planning to sell the house this August. We declined the offer of buying it ourselves and have now bought somewher else.

The dispute comes with letting people view the house. The estate agents are being a real pain in the ***, and are arranging viewings with little notice, and even a couple of times without our consent. Now the Landlord is insisting on his having a key so he can let viewers see the house himself when we are out.

I've been told by someone that we don't have to let anyone view the house while we're still paying rent, though in the contract we signed it does say that we do permit the Landlord to show prospective buyers round (like we read it all or realise the relevance of it all at the time!).

Is this lawful? Do we have to comply with our unreasaonable Landlord's demands, or can we refuse to allow anyone to view the house til we leave?

Thanks.
Additional Details
We've already shown a number of people round ourselves, and have had last minute cancellations numerous times which are very inconveniant. It's the Estate Agents that caused the initial problems by not listening to us, and not rearranging viewings to suit us. We're two very busy people and have already postponed our plans only for the viewings to be cancelled last minute.

The Landlord is now using bullying tactics, and forcing us to show people round, or for them to do the showing when we have already made clear those times aren't suitable to us. We're the ones being messed about here, and the only ones who have gone out of their way to help the others.