http://www.forestskillsltd.co.uk
I've had to re-create a complete set of new pages (ie cart, checkout, etc) and put them under a new parent page. These are all hidden, but the shop is now working again.
Wonder if it was something to do with a recent woo update. My last confirmed website sale was on 7th April so I've no idea how many sales I've lost out on. :(
Chris