Thanks for the info Deckchair, unfortunately this procedure doesn't work on the Stilo. You can't even lock the car using a remote with a key in the ignition turned to MAR, and it doesn't work if you lock the doors manually either :-(
I should qualify this: this was using an original key but with a replacement remote circuit board - the battery had leaked and corroded the PCA to such an extent that some of the surface mount components had fallen off, I got a replacement on eBay. It may however still work with an original remote that for some reason stops working.
KenN