Right so the tree line detail is what's getting me. Objects over open ground or in the sky are one thing but when they're specifically hanging just above trees it suggests something almost like... deliberate positioning? Like whatever it was knew the treeline gave it some visual cover from ground level.
Had something vaguely similar about three years back in Norfolk, mine was more of a pulsing orange light low over some woodland and I genuinely couldn't sleep properly for days after. Not because I was scared exactly, more like my brain just refused to file it away and move on.
How long was it hovering for roughly? And did it make any sound or was the silence part of what unnerved you? That tends to be the bit people forget to mention but its usually the most telling detail in my experience.