Sadly just looked on National Rail Enquiries website for trains on that date and sadly it appears engineering works are on again with division via Carlisle I imagine (like last year), so sadly it looks like I may be bailing on the idea again due to the increase in travel times and the fact the last train from Edinburgh appears to be at 17:55 meaning I would only have about 5 hours in Edinburgh, which is not really enough for me.
EDIT: I'm definitely not going anymore
Lothian Buses open day