Litigate against insurance firm

Having admitted liability, my home insurance company is using all kinds of tricks to frustrate the possibility of a fair settlement. Now almost 14 months has passed since the incident and there's no sign of a fair payment. The time has come to litigate. I need you to pursue them for payment with a law suite, starting with a "letter before action". You must be adept in uk insurance law and ability to know what you need to bring this to a successful conclusion.