How do I re-pressurise my Worcester Highflow400 Combi boiler?

The Pressure on my Worcester 400 Combi is currently at 0.6 bar after removing a radiator to decorate. The minimum indicator sits at 1.3 bar. Whilst working ok at the moment, I seem to have air in the system as the radiators are only warm at the bottom, how do you re-pressurise and do you bleed the radiators as you would normally?