Cheers both!
@Stephen L, good thought. I can see a workable square crop I think. I'm bad at spotting those! Something like this...

Theatrical by
dave.hallett on Talk Photography
Makes the compo more tightly focused, but loses the sweep of the harbour. Horses for courses, I think...
I've yet to notice any significant softening from the LT. It would only be in the corners if it happened at all, hardly a concern here. No, it's partly the ISO bump needed (underexposure due to high DR probably makes it effectively more like 3200 than the nominal 800), and partly that this lens doesn't get really sharp until you close it down a bit.
Cheers George, very kind!