Glowworm ultimate faulty boiler?

Hi, I have a "Glowworm Ultimate" boiler and I have just noticed a fault with it after the house started to get a bit cold.

The boiler isn't firing up. Every 5 seconds or so it sounds like something clicks on, a circular thingy at the top of the boiler starts spinning, something sounds like it clicks off and the spinner slows down. Then the whole process starts over again.

There is a spy hole and no flame visible through this, I don't know if boilers should have a pilot light on permanently these days or not.

Could anyone give me a clue what is wrong and if I can fix it myself? Otherwise I will call out an expert but I am wary of being ripped off so would like to at least appear knowledgeable when I ask someone Corgi registered to look at it.

Thanks in advance.