As you can see, mine is not a great photograph: there's reflection from the glass, the angle's wonky, and the picture is in any case somewhat faded from having been hung in sunlight for some years. Still, hopefully it gives you an idea.
Micky mentioned that the photograph was not unique: Diana had bought it from a studio, but it was one of a limited print run. Perhaps, if I did a Google image search, other (perhaps more pristine) copies might turn up?
I just tried that, and, by some kind of ambiguous magic, up popped this album cover:
This is the sleeve of the Adrian Snell's debut album, Fireflake (1975). You can hear it in its entirety here, should you wish, but probably the list of track titles will give you a sufficient idea of its genre:
A1 – I Was A Stranger
A2 – Song For John
A3 – My Soul Alive
A4 – This Is The Time To Say
A5 – Making Me Real
B1 – Gethsemane
B2 – Judas Song
B3 – Simon Carry My Cross
B4 – Golgotha
B5 – Jesus – Alive!
In some ways it's hard to imagine a more inappropriate set of songs to hum along to while watching those strange figures loom in and out of the fire, threatening to take you back down that not-so-bonny road to Hunsdon House. Adrian Snell is certainly not one of the acts Seb was so into. Still, I'm sure that DWJ would have been amused by the juxtaposition.