Withdrawing from contract.....advice pse?

I signed a contract early last September to have a conservatory built. The conservatory company volunteered to deal with the planning application, which was lost by the council but never chased up by the company. Having heard nothing by December I chased it up myself, which produced the information that the application was lost. It was then submitted again, the council admitted they lost it so only one charge was made.

I am still waiting now for this planning application to be approved and it is 31st March. In the 7 months that have gone by my circumstances have altered and I need to move house. I have told the company I want to cancel the contract, they are asking me for £2000 for costs and loss of profit. Can anyone tell me if this is fair or not? The total build cost was £13,700, but as planning is not yet approved no work at all should have been done. Planning applications cost £110 where I live, some drawings were also provided.

Note: There is no specific mention in the contract of a charge for cancellation, which I find odd. But nevertheless, I'm happy to believe the company is entitled to charge me something and I'm prepared to pay....but £2000 seems excessive to me. I've asked them repeatedly for a breakdown of what the costs are, how much is loss of profit and they have so far failed to tell me.

Thanks for any help