Indeed. This caused me a great deal of embarrassment on the
parade ground as well. Things are so much easier in drive side -
non drive side discussions.

To the OP, if we are indeed talking about the non drive side cup,
there are a number of tools that will allow better purchase than
an adjustable. If you have little holes in the cup, a pin spanner.
If two flats, one of these in the correct size:

http://www.amazon.com/Park-Tool-HCW-...125833&sr=1-21

But that is unlikely. In my experience (total of about 4 peugeots
owned) the adjustable cup was either pin spanner or the
aforementioned hex shape.

Many people will also advise a shot of penetrating oil
(PB Blaster - as seen on TV) allowed to soak and then
another right before your next assault.

Sheepishly,
Mike Larmer