No pilot light?

Hi guys,

My Ravenheat RSF 820/20 will not ignight its pilot light. I remember from before it used to make a clicking sound like a gas hob makes when trying to ignite it now - but the boiler does not do this now. Gas is going to the boiler and so is power. Pleanty of pressue and was fine the night prior to it not working. Did work fine the night before but after turning it off and then trying to switch it back on later in the eve no pilot light and wont light!

HELP!! Thanks in advance