dashboardhelp

This is the state of my dash at the moment :( 2L Diesel. Noticed a rattle/knocking noise from exhaust area when starting car at the weekend (from cold). I opted not to drive it since then. So I went to get more info just now and current state: - engine turns over and starts ok - first time...

I have a 04 Cupra & for about a month Ive had an engine symbol permantly on,in manual explains Excess Pollution.Ive noticed my fuel isnt lasting as long as it use too, maybe 250 per tank at a push How much can u get out of ur rides?Anyway Lambda Sensor came to mind any ideas similar experiences?