Buoy15, I only made the comment about it being a very flare, for I imagined anything chucked out of the bomb bay would be big and long lasting.
However I was there, airside, standing only a few feet from the parked Spit and P 40, and saw a flare from said Nimrod land between them. This was mid 1980's. Seem to recall it being fired as Nimrod flew along runway, and certainly not as high as 1500ft. Maybe things changed in later years.