While you have every right to expect all work being done for you to be carried out in a fit and proper manner, the Building Regulations allow some works to be done without going through the Building Regulation process. In most instances it is advisable to contact your local Building Control Department to verify whether or not the work to be undertaken is in fact exempt.
Full details of buildings which are exempt are given in Schedule I of the Building Regulations. At the time of writing some of these are as follows:
NB: A sun lounge is not exempt