I wonder what this was

[SamT]

That hole looks strikingly like Mam tor swallet on the bend by blue john cavern.

Reckon its probably artistic licence and he's 'cut and paste' it in to give some foreground interest.

 

[Mrs Trellis]

If anyone is interested here is the Wkipedia entry on Harry Epworth Allen - he was a WWI war hero :- https://en.wikipedia.org/wiki/Harry_Epworth_Allen

The painting in question is entitled "Derbyshire Walls"