PennyLane...

Very strange!

It's an interesting question and I don't know the answer either. I suspect it would hinge on whether you were seen to be exploiting a brand identity for personal gain. Exactly what exploiting came down to would be subjective, but I wouldn't think that if the items were merely incidental in a painting there would be a problem, but if it was the main subject of the painting being sold for a substantial amount then it might well be.

Certain areas are more critical than others too - for example images (including photos, paintings and caricatures) of football players or even using their team colours in a way that's seen to be treading on the toes  of official merchandising.

Sir  Mac(Cartney)