overheated - does this mean the engine is dead? renault extra 1.9d -?

hi all,
overheated my renault extra 1.9d, neeeds a new water pump.
The problem is though, that being an idiot with only 5 miles to go until st.agnes, i didnt pull over immediately.

The engine cut out whilst slowing for a junction at 15mph.

The engine has re-started (not for long of course) and sounds okay, (except the rattle of the water pump)

DOES AN OVERHEATED ENGINE THAT HAS CUT OUT MEAN ENGINE DAMAGE?
im wondering weather to bother fixing it as half the mechanics ive spoken to are saying "need to open it up to see if there is scoring damage done by the piston"
#i dont understand: how many people overheat per year?!! all those cars cant be scrapped...

any help would be greatly appriciated
thanks.