After looking at the image I made the decided to crop most of the image which resulted in the below image. The sky was added from the Westminster reproduction I did I have just layered it below the Charcoal image in Photoshop to give me a sense of what I'm trying to produce. Please Double Click the Images the the Largest size picture.
A more detailed version of the castle was produced by relooking at the photograph with pencil, once I was happy the drawing was then scanned into the computer and replaced the charcoal image.
The image was then transferred to canvas by using Royal & Langnickel Graphite paper, I use this all the time it does the same as carbon paper but it leaves a graphite mark on the canvas which can be rubbed out easily. They also do a white version as well as the grey one I've never used the white one but it’s good to know they do it if you ever need it in the future.