Noisy Boiler?

I have a 2006 Baxi Combi boiler and every time the boiler reignites when i have the heating on, there is several loud clicks coming from inside the bolier which are very noisy. It clicks around 5-6 times and then stops until either the next time the boiler reignites or when I turn the hot water taper or shower on.
I have had the boiler serviced, put in some fluid to reduce noise and checked the pipes all without avail. My boiler engineer thinks it may be an electrical problem inside the boiler?