So, a very nice man from teh gas repair company came to fix it. He ahd teh part orderd with teh number and reference from the boiler...
IT DIDN'T FIT!!
Apparently the style of boiler we have is notorious for breaking dwon. Great. Oh and without this part being fixed? We're stuck with water hot enough to scald in literally seconds. Guess I'm still bathing the girls in the baby bath then.
I did ask how much it'd be to get teh oven sorted out (remember the 3hr chicken that was still raw?) Got told it'd be safer and cheaper to replace it. Defintley DON'T try to adjust the thermostat myself (like the landlord said when we told him)