Increasing the strength of the shadow?

You've got it mostly ok already, but just imagine that you have laid the mountain down on its side like a gigantic fallen chess piece. the shape of it represents the shadow it might cast. You might see that there are more jagged bits at the top of the shadow.

I am not sure I fully understand what you mean about changing it all into lines.

If you mean that it turned everything into zero width lines, then using Change Properties to give them back their line width should have worked fine.

Anyway! I'm glad you got it all sorted out :)

Well, aside from the colour, it doesn't really have anything in common with Viper's Bugloss (which is what we call that weed).

Heath is a mixture of Erica and Calluna species (heathers), Ulex (gorses) and lots of grasses and other plant species all mixed in together. Its a naturally evolved ecosystem that supports a large number of increasingly rare fauna in the British Isles, including the the Silver-Studded Blue...

...a butterfly that has Protected status here in the UK. 'Heath' is the lowland cousin of the Scottish moors. Much of Wimbledon Common once used to be a heathland.

It's not a sterile monoculture of a single invasive weed.

That's good :)

The walls and towers could be done the same way as the roads but you have chosen to go with symbols, which is fine.

It's looking really great. You're rapidly becoming a really good mapper :)