Here is a copy/paste from RAVE:
FUEL DELIVERY SYSTEM - TD5
Fuel system purging
If the vehicle runs out of fuel, or the fuel level is so
low that the fuel system draws air into the fuel rail,
the fuel rail will need to be purged before the engine
will start. This can be achieved by following the
procedure below.
If this procedure is carried out on a vehicle that
has not run out of fuel or otherwise drawn air into
the fuel rail, it can lead to the engine flooding and
failing to start.
Purge
1. Turn the ignition switch off and wait 15
seconds.
2. Turn the ignition switch to position II and wait 3
minutes (this ensures that the fuel system
purges all the air from the fuel rail within the
cylinder head).
3. Fully depress the throttle pedal.
4. Keeping the throttle pedal fully depressed,
crank the engine.
5. As soon as engine speed exceeds 600 rev/min,
release the throttle pedal and the ignition
switch.The engine must not be cranked
continuously for more than 30 seconds at
any one time.
6. If the engine fails to start, repeat the above
procedure.