I am not sure what a Micra is but take it that must be a european
Nissan of sorts?

When the car stutters, does the engine speed drop? In other words, if
your car has a tachometer (RPM), does it drop in speed?

If the tach drops, it most likely isn't clutch but engine related. If
the tach stays the same or rises, it most likely is clutch or tranny
related. If so, whatever is stated below does not apply.

If it is engine related, it could be many things, all related to
different subsystems (fuel, air or spark).
If so, I'd first try to run some injector cleaner through a full tank
of gas ("petrol" for you most likely :) to see if that helps -- it
certainly never hurts.
Ask your mechanic to also check the fuel pressure. (It is a little
surprising he doesn't know what to check next, because that's a pretty
normal thing to check for)

If he replaced the distributor, most likely the wires and plugs were
replaced as well. If not, replace them too.

Some cars have dual fuel filters, so you may want to look into a repair
manual (read it in the bookstore or library) for your particular car to
see if that is true in your case. Often one resides near the tank, the
other under the hood.

All newer cars (96 and up) have an on board computer that can be read
with a special tool, called an OBD2 reader.
If something went wrong, the event is recorded in a log that this tool
has access to. If your mechanic does not have such a tool, you may want
to bring it somewhere where these codes can be read.

Hope this is useful to you and you get it fixed soon.
Remco

<snip>

Tibby,
give us a clue:  Is this a K10 (squarish old model micra) or one of the
newer rounder ones, or even the latest one with the popeyed headlights?
 The K10 had a carburettor engine, and the likely causes are all different.

HTH

Andy

What makes you think there was water in the gas?

What did you do to get rid of the water in the gas?

Water in the gas isn't going to damage the distributor.