Currently having intermittent problems starting my 56 plate Diesel Mondeo.
It gave symptoms that the battery was getting dead, dashboard lights flashing and failing to turn over.
Had exactly the same problem with my previous Mondeo, and upon fitting a new battery, the problem was sorted.
However, I have replaced the battery with a brand new High Performance battery, and the problem is still present.
Sometimes it will start fine, but then on every so many start ups, it gives the indication that the battery is dead and it is struggling to turn over. If you then turn the ignition off and try again, it will start fine.
I am thinking that it might either be a problem with the starter motor or the alternator.