Right so this thread caught my eye straight away. I'm up in Northumberland and we get some genuinely odd stuff over the tree lines out here, mostly written off as drones or military aircraft from the bases nearby but some of it really doesn't fit that explanation at all.
What colour was the light? That's usually the first thing I try to nail down. There's a big difference between the warm amber/orange stuff people report and the cold blue-white flickers. Also did it make any sound? The silent ones are the cases that stick with me.
I had something similar about three years back, just sitting in the garden and this object was just... stationary, no wobble, no drift. Watched it for maybe four minutes then it was gone. No gradual movement, just gone. Still cant fully account for it.
Post as much detail as you remember while its fresh. Time of night, wind conditions, how long it lasted. The details people forget after a week are often the most useful ones.