Landlord - tenants issues, please help

[QuintessentialShadows]

I posted this thread here and it was suggested I repost in legal.

Bascially, we rent. We pay a fortune per month for a 3 bed house in a desirable location. We were also letting our own property long term. This subsidized our rent.

Our own tenants gave notice, and moved out this weekend.

I emailed my landlord in June explaning that with our own tenants moving out, we would struggle to pay rent, and could we be released from our contract early, preferable 1st August. He said he would discuss with family and get back to me.
We have a 1 year contract, ending 12th September. 6 weeks deposit is in a protected scheme. The tenancy agreement says that a tenancy can be ended early if we we find replacement tenants.

Upon not hearing from my landlord for nearly two weeks, I emailed again asking if they had a chance to talk about the situation. I said I had a family who would be keen to move in and stay until at least the end of September, as they were going to do building work in their home and needed temporary accommodation.

The landlord replied back saying they had agreed to put the house on the market and would agree to let us move out early, if they found tenants before the end of our contract. Could I please get in touch with the agent to get the balls rolling. Which I did.

Since then, there has been a number of viewings, we have worked hard to keep the property in really good condition for viewings, tidy, clean, etc.

I was just informed by the agent that there has been two offers on the property, but the landlord has not been getting back to the applicants, taking so long time to respond that the applicants have had to retract their offers to secure another property, obviously being keen to find somewhere to live.

Where does that leave us? We have paid rent up until 12th August, we are moving out on the first. We first found temporary tenants, which were rejected. The landlord has then had two offers, which has been ignored.

Can they still hold us to the original contract, where we have to pay rent up til 12th September?