Well spotted, sweetcheat! You may notice that at the base of the tree I have painted the swirls and spots of the rock art from Gardom's Edge. Many thanks to common era for bringing this haunting motif to my attention.

I've now produced a very limited print run of this design as xmas/winterval cards which are for sale in my online shop:
http://www.janetomlinson.com/shop

Sorry for the blatent sales plug... I've prevaricated for ages about posting this.