I have the above combi boiler. To the best of my central heating
knowledge it is a 'sealed' system.

I want to fit a new radiator in place of an existing one. The plumbing
bit i can handle, i.e the physical joining of the pipework. But i am
unsure how to go about the draining / refilling of the system. Does
anyone know this boiler and / or have any advice or hints?

Thanks in advance.
Gerry