Unfortunately, I cannot recommed anyone for demolision, but just wanted to mention a problem that my friends had with the demolition of the house on their land.
When signing a contract they didn't put a time clause as to WHEN it's going to happen. The demolition company was delaying the job and the whole process was dragging on for over three months, but because the contact was biding my friends couldn't get out of it to sign a contract with another company, and they could not progress with the bulidng of the new property. I suppose they could go to court but this would only cause them additional hassle and costs.
I suppose the similar problem might happen with companies that buy houses and take them away from your property.
You might have been aware of that trap already, so sorry if I repeat what you already might know .
PS. Please let me know how you go. I would be interested if you find someone and are happy with them. We might need to use the similar service in the same area in not too distant future.