Thanks for the pointers. Have now bled at both the tank filter and the pump end and its been ok for 2 hours. (which is about 1 1/2 hours better than it was doing!)
Tomorrow - I'll check the oil is running freely as you describe and on Monday I'll be arranging to get it serviced. We've only...
My Myson Velaire Oil Boiler (prob 12+ years old) is locking out - and its increasing in frequency.
Seems to have started last week. We had an oil delivery very early on a Sat morning, which caught us on the hop. We didnt realise its was being delivered until they posted the Del note through...