Peugeot 307s Petrol - AntiPollution Fault Plus?

Peugeot 307s Petrol Automatic 53000 on clock

Just changed the remote battery in key fob - nothing else - went to start on frosty morning, starter turned over but engine didn't fire. No response from throttle! After many attempts (15+) eventually started ticking over - still no response from throttle. Switch off, engine kept running. On & off and eventually started but AntiPollution Fault light & Engine Diagnostic Warning Light Came on. Reading previous it seems pointless taking it to a main dealer as the solution will cost more than the car.

Any suggestions gratefully received