I've changed my front speakers in my Fabia but would like to fit back ones, however i have noticed that wires have not been run. could anyone give advise on how to run wiring from my standard Symphony head unit to speakers in the back? cheers.

Usual place is along behind drivers parcel shelf, down A pillar lower trim, underneath sil kick plate and trim, past B pillar, behind rear wheel arch trim and into boot. If you don't fancy ripping half the interior out, the wires can be tucked behind trim panels, at the cost of a few cuts a bruises, but a lot less swearing.