Thanks for the responses, at least I now I'm not going mad.
My landlady got back in touch with me and gave me the number of the installers, looks like in my panic I posted this problem a bit prematurely :oops:. I'll be having a word with them tomorrow all this.
Over the weekend I lost hot water and heating and checking the boiler showed that the pressure had dropped to 0.5 bar (the display was flashing between 0.4 and 0.5). I tried to follow the instructions on the boiler to fix this but I couldn't find the taps it was referring to. I've looked at the...