306 cabriolet won't start

[GuyTom]

Thanks for responses much appreciated.. After visiting the local scrapyard, I now have a new barrel and 2 new (old) keys, have fitted the barrel successfully and the starter engages now, but still the b. won't start. (I have taped the old key next to the transponder but maybe it is confused getting 2 answers (seeing 2 keys)). Though no hint that the immobiliser thinks there's a problem - no red flashing led from the dash... Anyway to verify? Or ideas??