What is the warning light that keeps flashing up on my Ford Fiesta?

I have just bought a Ford Fiesta 1.0 EcoBoost and an audible warning is intermittently sounding. A warning flashes up on the dash but disappears before I can read it. Any ideas?

How do I keep a petrol particulate filter in good condition?

We have a Fabia TSI automatic and live in a rural area so speeds are low and limited to 30mph for miles around. The auto keeps the revs as close to 1500 as it can so there is no way to drive at 2000rpm....