Anti pollution fault and management light

[Aclynshaw]

Hi people
I know this to be a common problem with Peugeot 206 petrol 1.6 2003 but the anti pollution fault came up on the dash with the management light.
I have changed the lamba sensors and cat, the light went off when l left the engine running for over half an hour l left it for a couple of days and when l started the car the anti pollution light has come back on any ideas would be welcome.

[Spitfire6]

Give it a good thrashing for a while. Getting the oil temp to 100 is the right type of load.