There wasn't any extreme pressure in the system, just due to the cold, the trv's opened with their frost setting lol
The boiler wasn't running during the night as I had a few leaks, didn't want to deal with them, (slow leaks) so pressurised this morning, thats then the trv's opened up, (I'm not an expert on central heating or plumbing) you can probably tell haha
Tomorrow I will get some blanking nuts, stick them on the trv's, then re-pressurize the system and bleed the rads accordingly, I need some heat in this house :O Everyone else has vacated, I'm the only one left, I'm a coldy but this is rediculous :O