First, I must point out that Jonny’s Les Paul is not a Goldtop. It is a Gibson Les Paul Standard in “natural” finish. If you search for photos of other natural finish Les Pauls from the late-70s and early-80s, you’ll see that they often have a slightly golden color, probably from aging.
As for the strap, Jonny has used both a black Ernie Ball Polypro strap (just about the most generic guitar strap you can find) and his old brown plastic-buckle guitar strap (visible in the photos below). The plastic-buckle strap is similar to the discontinued Levy’s M15 strap, but there are some notable differences… Jonny started using the brown strap around 1996, so it’s very unlikely that it’ll ever be identified.
You can read more about Radiohead’s guitar straps here.
A photo of Jonny performing Steve Reich’s Electric Counterpoint at the 2014 Big Ears Festival (pastemagazine).
Jonny’s Gibson Les Paul Standard and Fender Super Reverb Amp on stage before his performance of Steve Reich’s Electric Counterpoint at the 2014 Glastonbury Festival (synergyvocals.com).