The B1442 is a fan and conventional oven. This means it has 2 sets of elements.
Are you sure the fan oven setting is not heating AND that the conventional oven setting is not heating?
If just one setting doesn't work, suspect the element associated with that. If both dn't work then, either one had already failed and you hadn't noticed until you tried it just now OR something common to the two sets of elements has failed, like the temperature limiter (though I would wonder what made that trip).
More info here:
https://www.justanswer.com/uk-appliance/37oiy-neff-b1442-oven-stopped-heating.html
http://www.espares.co.uk/search/ma1126pt1595/cookers-and-hobs/elements/neff
http://www.espares.co.uk/search/ma1126pt1604/cookers-and-hobs/thermostats/neff
acp
July 2017