Thanks all for the great answers and explanations.

AM, I will try the Warp tool in PS CC.
Glenda, noted. I'll give this a go.

Perspective distortion? Yes, that is it!

I think this distortion was unavoidable in this situation which at least has taught me to use some tools in PS CC that I've seldom touched.

In taking this shot I found I couldn’t move back any further (only another 2m available to do so anyway) without bringing into shot another of the ugly sheds (LHS of where I stood) on site. This also meant framing the lighthouse in portrait with it left of centre in the frame. I wanted the path leading off into the distance to give perspective and depth to the shot and avoiding the LHS shed brought the path into shot anyway.

All told an overly complicated shot saved by the magic of PS CC.

Moreton.jpg