All sorted now.
jrussel was spot on with his diagnosis and was right that both hoses were disconnected
The hoses were the fuel overflow and tank breather (Numbers 6 and 7 on the diagram below)
Although the dealer tried to distance themselves from any responsibility, they are the only people who have removed the tank!
Obviously fixed free of charge.
Interestingly my friend has had 2 issues with the bike in his 2 years of ownership (bought new) both caused by the dealer.
Thanks to everyone again
Mike