Hi, When my central heating first comes on there is a loud intermittent banging in the bedroom radiator. This continues for about 15 minutes then moves on to the second bedroom (right behind my headboard!) and sometimes comes back. Ive bled all the radiators a few times recently and Ive had my backboiler (Baxi) serviced by British Gas in August. The noise is really loud and keeps me awake... Please help its driving me crazy!