Spent a few hours this afternoon messing around with layer masks and some of the G'Mic filters. I'm not sure if the end result is a disaster or a pretty cool affect, I quite like it though so I'll side with the cool affect way of thinking.
The original picture - the top one - is a bit out of focus which is why I decided to do some serious manipulation work on it and not just leave it as is.
It good to experiment, you never know what you'll find.

I really like the colors of it. It gives it a kind of strange surreal quality.

The picture is indeed quite nice and the lack of focus is a pity. But I'm not convinced by your fix, IMHO the blue tone just makes it look like if in addition your white balance was not set properly. And you should correct the 2° tilt to the left.

My suggestion: Tools/GEGL/C2G with very low settings (radius/sample/iteration) to get a very grainy look,
followed by a gradient map (here, #A80000 to white):

I really like the Blue Grass one Caz. Very cool.

I LOVE the red, grainy one. The texture through the whole image is wonderful. Those clouds, the grass, the boat ... everything ... WOW!

Thanks everyone, it's good to hear the different opinions on which looks best. And now that it's been mentioned it does look like I had the white balance set to tungsten, could've save myself a lot of time if I'd done that in the first place.
Cheers for the tips on the gradient mask, ofnuts, I'll give that a try. It makes for a very old fashioned look which I think is pretty cool. Didn't notice the horizon tilting to the left btw, the things I miss.

Most of my pics have a 1.5° tilt to the left. That's why I don't frame them too tightly when I shoot, because the straightening up eats some of the sides.

I like it also because it remind me the effect of colour infrared photos (to not be confused with normal BW infrared, the emulsions for coloured infrared are from long no more available and anyway are no more lab that can't handle them because they required special chemical no more available
Alas there is not as far i know a digital equivalent )

About the red i like much the grainy look but then i would prefer in black and white..

Nice photos Caz but I think I prefer the original.

Thanks, he4rty. I'm keen on the original one too, but it's a bit out of focus and I think that's what lets it down. The place where I took the picture isn't far from where I live so I'll pop down there again one day soon and try for a more in focus version, and probably get muddy boots again like I did last time. Ah, the joys of a tidal estuary.

Nice version of the picture, PhotoComix. I was trying out the C2G filter as well last night. It does seem to make the sky very grainy but I like the antique quality it produces on the rest of the picture. I'm going to play around with it some more and see what I can come up with.

Thanks for the tip on not framing too tight, offnuts. Good advice that I'll keep in mind.