Sudden coolant loss on 306 XSi

Hi all
I have an aging Peugeot 306 XSi ('95, 'N' reg). It had the head
gasket replaced several years ago. Recently I've been having
intermittent problems with overheating & loss of oil & coolant, which
I've managed to mitigate this by paying attention to keeping things
topped up. I had a friendly local repair guy check it out and he said
the head gasket was starting to go,but was still OK for now. So I
realise I'm on thin ice at the moment...

Anyway, last week when parking I noticed liquid stains on the ground.
From looking under the car I could see liquid dripping from what
looked like the underside of the engine, driver's side. The liquid
looks like coolant, not oil, & the coolant level is way down.

Although something important is obviously wrong, this doesn't seem to
be what I'd expect to see if the head gasket had actually gone. Any
thoughts on what might have happened and what I might do to check it
out, prior to getting a garage to have a look at it (or scrap it ;-
( )?

Thanks for your thoughts.

Regards
Jon N