"The warmth of my end place"?
Of course my horse!
I picture the underground place as a mausoleum, "end place" fits so nicely there, thanks Resonator.

So what are the images I get, strangely enough they're similar to those of Noel.

But if the Time Being is Kilbey I've usurped his name!:)

I picture the Time Being as resting in a mausoleum, tired of living through the ages. Is not necessarily a corporeal being, it maybe a Being that can enter and bring life to statues of stone, "strange turbulence fill the air" as the Being animates the gargoyles and winged monkeys, but maybe that is just a dream... and the being jumps back into himself.
I picture the winged monkeys a carved statues, placed near traditional gargoyles, maybe atop the mausoleum, maybe in a nearby ancient building that the Being saw and maybe even lived in at a previous time, before retiring to his solitude.

But is a time of change, the refuge has been penetrated, the barriers eroded, and at the end the Being strives to live again, leaves the chamber and goes away, into the sky, and maybe beyond.
I never thought of "lightning and thunder" as a nuclear blast but seems fitting.
I think the lyrics to this song are almost cinematic in their capability to evoke images.