Maxol boiler - pilot light intermittent fault?

Hi there,
This is my first post. Please help! :?

I have an intermittent fault with my boiler. Heating is on a timer - sometimes the pilot lights as usual, heating comes on for a while & then pilot light goes out, heating goes off, house is freezing. I manually press reset & it works again for a while only for the same thing to happen again...

Or pilot light doesnt come on at all (when timer does), I manually reset and it is then OK for a while.

My boiler is a Maxol Microturbo 50 (and I can email the manual to anyone who is interested)

Thank you!!