Exercise: scaling up from a photograph

The aim of this exercise was to find a scene with an interesting subject in the middle distance. I finally found this scene in a local park. which I think is an Edwardian shelter, and photographed it with the railings framing the foreground of the image.

This is the photo:

I then marked up the photo with a grid and scaled it up to an A2 sheet of paper.

I used a mixture of soft graphite pencil, and then watercolour pencils to do most of the picture. I did apply water to some parts of the picture just to give a softer look to the colour. I finally used a black marker pen to do the central shelter in order to bring it out.
The sky was virtually white and so I've left that blank.

Here's my version: