Making a 6 inch Christmas Cake

Hi Lindsey, I've used Delia's Christmas Cake recipe for many years but this year I thought I'd use the recipe but bake in a smaller cake tin.
I'm using 6" round tins instead of my trusty old 8" round tin.
Would I bake the smaller cake for minimum 4 hours or should I scale the time down a bit too ?
If so any guidance on how long to start with.
Many Thanks
Douglas
ex-pat Scot living in Portland, OR, USA