Way back when I was an impressionable teenager I read a Mills and Boon novel called Leopard in the snow, which followed the usual format as it told the tale of a woman who got lost in the lake district and was rescued by a mysterious man who lived in seclusion with a leopard for a pet after an accident had left him crippled or something very much like that.

The Tower of Silis Bonnoenfant follows something of a similar patter. Marion got lost in the southern plains and crashed her car into the Caldera and was rescued by Silis, a man whose only companion is a semi-tame leonate and who lives in a tower hidden by a chameleon cloak. He is gruff and apparently unfriendly while clearly taking good care of her. The difference between Silis and the reclusive Dominic Lyall is he fully intends to make sure Marion gets home, and he actually does have a deep, dark secret. He is a former prisoner of Shada, wrongly accused and still bitter after being released at the end of his sentence.

The location of the Tower was inspired by a picture I found on the internet. It is so long back now that I can’t remember where I found it or under what search criteria, but it struck me right away as a place that had to come from either magic or Time Lord technology. The tower ought to fall down. It is too thin and too high. And the lakes are clearly alien. So it came together as a place on that mysterious planet called Gallifrey.

http://www.fantasticfiction.co.uk/m/anne-mather/leopard-in-snow.htm