Worcester Danesmoor 26/32 lockout issue after return from holiday?

Dear all

Our Danesmoor oil boiler, fed from above ground tank in the shed, has locked out on return from holiday.

We missed an annual service this year (as money is tight). The oil tank is full and I have bled the oil pipe, and restarted. The air pump goes for about 10 seconds, tries to light but never makes it. Switching off and on gets the air pump to blow for another 10 seconds, but we get back to the same place we started at.

I'm not really well qualified to play with these things - any ideas would be appreciated.

Thanks very much

Damian