Noisy vibrating oil central heating system

Please can u help.

We had a new boiler installed just before Xmas. Its is a wall hung exterior oil boiler (GAH Thermecon W50/80E) at the same time the position of the hot water tank was changed, various radiators were updated and 3 new added.

Since fitting the last radiator (About ten days ago) the system seems to be full of air - there is a lot of banging in the boiler although the rads seem to functioning ok (They are not showing the classic signs of air in system i.e. cold at the top) However on Saturday evening things got much worse -the boiler was vibrating so much that it was causing the walls around it to vibrate as well. We turned the theormostat on the boiler down and this seem to cure the problem - however this morning the vibration was back. Is this due to the air in the system - or would it seem that the boiler is malfunctioning - the plumber is back in again today but some independent advice would be very welcome.

what type of system

I think it's a fully pumped system - 3 valves and control box - 1 for upstairs, 1 for down, 1 for hot water - does this make any sense?

have checked the valves are working
by the sound of it you have a curculation problem
might be worth checking the bypass (if fitted)

Excuse me for being dim - but what's a 'bypass'?

The plumber is here at the moment - I just need some information/ideas so that I can talk to him about the problem