How do I choose the best standard form of building contract to limit my liability?

They establish a common starting-point and are codified in the Supply of Goods and Services Act 1982, which itself forms a neutral basis for evaluating standard forms of contract. Part II of the Act states:

13. Implied term about care and skill. In a contract for the supply of a service where the supplier is acting in the course of a business, there is an implied term that the supplier will carry out the service with reasonable care and skill.