Not had any problems with the car, a 1.2 2005 model, for quite a while so was expecting something! ( its a panda owner thing!)
Today the engine failure light came on which after a few restarts is still on.
looking at the manual its says it a problem with the supply/ignition system.
The car had a dose of redex on its last tank and was filled up yesterday with 97% petrol.
Ive used this grade of petrol before with no problems and the exhaust fumes smell normal.
So before I try and find a garage that can sort this out, is there anything I should be looking out for under the bonnet?

I take it you mean the little yellow "gearbox" looking light?

That comes up when there's a fault with the engine....not necessarily the ignition system, virtually any sensor on the engine will throw up the fault light.

Easiest thing is to plug in a code reader. That will tell you exactly what the issue is.

I use an app on my phone, paired with a Bluetooth obd reader. If you don't have one, it is well worth investing £10 in one for the future.

Get a bluetooth OBD reader ELM 327. Less than 10euro
Download MuliECUSCAN. Free edition.
Read codes. Free
Tell us what the fault code is.

Well the engine fault turned out to be connected to my service I had a few months ago.
The fault was a mis firing number 4 cylinder. On closer inspection it turned out the cable wasn't even secured to the top of the spark plug so over a period of time the vibration of the car starting had moved the HT just far enough for it to occasionally make the connection to the spark plug, we also found cylinder 3 HT also loose!
Anyone who has read my last post regarding fumes in the car where they snapped off a retaining bolt for the airbox! so they just let it rest on top of its mounting with the breather pipe emitting the engine fumes!
Apart from the mot I don't let them near the car, its a better the devil you know syndrome!
to finish off...now all the HT leads have been reattached securely she runs sweet as a nut.

Excellent.

With wasted spark systems its reasonably easy to diagnose sparks problems.

One plug missfire or a pair that involve both coils -
Two plugs missfiring -