Dash gone t*ts up

We said good bye to the dash on saturday. Took eldest to catch train (14 mile trip) with 1/2 tank of fuel (230 miles left in tank) acording to the dash. When i arrived at the station only had 25miles left (mpg bad but not that bad).When i turned round in carpark suddenly got a full tank. On the way home car juststopped and the dash had a fit and gave up. Restarted but drove home with no dash. Dash is now working when it feels like it. Goes in on thursday so let you all know how i get on.