While it's tricky to attribute specific qualities to players in a trio as collaborative and experimental as This Heat, by all accounts Gareth Williams was the joker in the pack. Just the berserker disillusioned prog Charleses Hayward and Bullen needed, he seems to have been equal parts Eno and Macero, exploiting chance and naivety then splicing the results into uncanny new studio life. Williams' found sounds, junk percussion and toy instruments bought a much-needed playfulness to the group's apocalyptic overload, rooting it in human foible and suggesting life among the ruins.

These tactics for breaking down the structures of rock to release new energy – torched songs – were complemented by a shared curiosity about, for want of a less wholefoody shorthand, world music. If this gave Deceit's dystopia horrifying global reach, it also sneaked in a seductive, insinuating richness. Who could resist 'Sleep''s fourth-world spell, even as they clocked where its mordant doublespeak was directing them? As it turns out, that ethnic instrumentation (and I'll warn you now: the specifics on this front will remain lost in the gulf between my ignorance and Williams' expertise from here on in) also seems to have signposted an awakening of sorts.

Soon after Deceit was recorded, Williams left This Heat and South London for Kerala and Kathkali, the classical dance theatre he studied alongside religion, music and other aspects of Indian culture. Judging by Flaming Tunes, along the way he found a framework – musical certainly, philosophical probably – in which to focus the chaotic tendencies let loose in his old group. Sadly, this collection of home recordings, made with Mary Currie and a houseful of collaborators, and released on a limited run of cassettes in 1985, is all we'll hear from his time after This Heat (cancer claimed him in 2001, aged just 48). Happily, it's packed with precious examples of music as unassumingly joyous and syncretic as Don Cherry's finer moments, albeit arrived at through very different routes. A rare kind of compliment, but then it's a rare kind of record.

These tunes don't trumpet their achievements; they could sound slight or polite passing through your daily information feeds. But something in their composition always catches you, draws you back in. After a raw, two-note herald from (I think) a kazoo-ish wind instrument, 'Beguiling the Hours' arrives like a street parade. It's a hearty sing-along in the mode of Brian Eno's Taking Tiger Mountain (By Strategy), with a similarly decentred rhythmic assembly of pub piano and hand-claps; the motion of an elephant rather than a motor vehicle. We're celebrating what happens when you let go of time, by warning about the consequences of clinging to it: "A thousand precious thoughts . . . devour us." This Heat's red alerts have been transmuted into eternal reminders: "The emptiness constantly carries you outside yourself / Away from any satisfaction." The song passes, leaving the sound of human traffic in its wake; horn blasts and percussive clatter slip out of time and go their own ways. By contrast, the refreshingly direct 'Breast Stroke' is located firmly in 80s London. It could be the best song Robert Wyatt never wrote: a simple appreciation of watching a loved one swim, with a meandering, friendly melody that could go one lap or a hundred and keep you involved. Here again, time isn't after us.

Often in song, what gets called joy is really relief: from longing, loneliness, anxiety. Here it's felt in being, sunk into. 'Restless Mind', the record's centrepiece, is a sort of meditation anthem that uses repetition to cultivate stillness (as opposed to the propulsion it produced on This Heat's, uh, 'Repeat'). A crystalline three-note string riff rings regular as clockwork, with subtle variations. The four-line focus – "My body looks forward / Its restless mind runs back / It's just like a banner that flaps in the breeze / You’ve got to work to hold on to it" – drops in and out; so do strident Indian drums. The music could almost be a daring dub by Shackleton, except his quiet hours sound so much more filled in. Williams' tunes are dips into the stream of time, built not to resolve but to keep rolling. The musical disciplines he studied favoured marathon performances, after all. 'The Best Weapon' ("learning", since you ask) is based around a repeated, raw guitar arpeggio like counted breath; a warm harmonium(?) melody/bassline provides occupying motion for the vocal to follow in devotion. No destination, just a trick to make you feel stationary and content.

When the singing falls away, the sense of arrested time is stronger still. 'A to B', round upon echoed round of (I think) struck string instruments dancing in (to me) unfamiliar scales, produces minor, giddying variations, like the moon's reflection on water rippled by a breeze. This kind of ambient attention makes for the prettiest piece here: the poetic piano line of 'Raindrops from Heaven' rises from and falls back into an ecosystem of artificial insect rustle, bird chirrup, and sheep bleat.

If any of this suggests sanctimony, blame George Harrison and his dreary solo efforts. It takes humour and humility to get this stuff right, and Williams had both in spades. Flaming Tunes begins with a Fisher Price gamelan built from rudimentary plink-plonking, cack-handed drum machine and slapstick tape noise (and it's really good!). If the pleasure he took in sound is evident throughout, so is the formal study he'd put in. The quirky soundtracky numbers here find the lo-fi prankster/Technicolour studio whizz we know from This Heat still hard at it, only with new, intricate compositional tricks up his sleeve.

All these tendencies come together on the enigmatic 'Golden Age', where Williams plays the holy fool. It opens with a pantomime chant – "One step forward, two steps back" – and goofy, well, I'm going to call it a 'twang stick'. But complex melodic turns and guitar rounds soon flood in, creating a deeper sense of frustration with lack of progress – perhaps with meditation practice, perhaps in a grander, apocalyptic sense. Either way, time goes out the window again. It's one weird piece of work. After all, what is a flaming tune? A gift handed down by a seven-tongued fire god? Or something flaming Nora could sing along with?