@Paul Huntley I agree with @Robert Reichard , and also I would make trees in cloud shadow on the opposite side a bit cooler and slightly more saturated:

It will be great one 👍

I like your brush strokes and successfully painted shapes with simple strokes. Water is OK, lights and shades are missing everywhere. The sky is nice but too warm as for me

You learned how to catch the light 👍

Certainly some traces of mountain reflections should be visible on the water surface. But my eyes first of all noticed uniform shapes of trees, like plantation grown for Christmas which is OK if you want to show them like that. But trees reflections do not look right, many of them have wrong length and all of them are just repeating original subjects' values and hues. Reflections, as well as perspective, are all about physics and math. It depends on its position, which part of subject will be visible on reflection . In reflections darks are looking lighter and lights darker.