I understand that it hasn't sat for long but would still routinely check above and since looking at pictures, need to add fuel cock - in fact I have a hunch I might try that first.
I checked quite a few of the above but still no luck. Sadly I think i've got to the point where it's got to go into a mechanics as we're starting to pack everything up for the house move and I've run out of time. I'll let you know how it goes. Thanks for all the suggestions! Always appreciated.
I will have washed it at some point. I don't remember if it was just before this happened but its possible. The tank was fairly empty when this happened. Think the light had just come on so I topped it up to full thinking maybe there is something dodgy in the fuel tank but it didn't make any difference.
Also, if you have water in your tank, petrol will float on top of it, so putting more fuel in will not help as much as you might think
I was suggesting water or debris in the fuel could be your problem but yes, draining, flushing and refilling with fresh, for the cost of it, would certainly be worth a try. You would need to drain and flush your float bowls as well. There is a horizontal drain screw on the bottom of each bowl.