Margaret Shaw - Artwork - WiP Harbour Dusk

I encountered this stunning image whilst on holiday on the Moray Firth.  A wonderful place for sunsets and dusk.  As a  matter of face it's pretty wonderful full stop - but I diverse.
I've done the initial drawing from the photo on the I pad and now I'm on the laptop
I can already see a few tweaks that need making but I'll do those at the transfer to art paper stage.
I've also drawn at A4ish size but am wondering about a scale up to A3ish.

Left it at A4 and decided to have a play with some recently acquired Derwent Art Bars. 
Here's the initial layers - not happy with the sky as I'm not getting the dark / light contrast I'm looking for.
Maybe I need to read the leaflet on how to use your art bars or change to inktense bars for the darks.

Continuing with the artbars, I read the instructions in the tin and have changed
the approach to using them more like pastels than watercolour paints. 
I'm getting some of the darks, but there are allot of blotches on the paper
and overworked colours loosing the lights - could be a re-start
or maybe some other media to re-establish the lights?

Continued to work with the artbars and have now lost all the light and have an overworked sea and sky. 
But I prefer what I've done to the rocks.  Time to change media to re-establish the lights.