Looking at visiting a few friends at the Edinburgh Fringe in August and was astonished at the low Caledonian Sleeper seat fares from London. £15.75 each way with my 16-25 railcard - and in the middle of the festival season, which given the high demand is a brilliant deal if perhaps not quite as good as the £8.60 each way I paid on East Coast in 2010! The trains depart from Euston, but it also calls at Watford Junction which would be slightly easier/cheaper for me to get to. However, if you try selecting WJ on the sleeper.scot booking website it gives 'FULLY BOOKED' message for every day you try, both ways. Does this mean alighting and departing at Watford Junction isn't permitted? If so, then why does it list it as a valid option when trying to book?