Some experimenting today, using a 10 Stop Neutral Density Filter from Nisi and also a ND8 09 reversed Graduated Filter from a company called 84.5.
Taken at 3pm in quite harsh sunlight, I am not completely happy with the result but it may just that I need a little more practise using the filters. I was getting some vignette in the top left hand corner and a slight magenta colouring.
Something to think about next time !
I was using a Fuji-film Xt1 with 1824mm Lens at F16 and 5 seconds