If one of the low beams is still working then the working bulb connector can be plugged into a harness like this....
Look on Ebay for H4-9003-Headlight-Relay-Harness-Wire-Halogen-Ceramic-Controller-Socket-Plug-Kit-/
The body computer now just has to feed an amp or so to the relays for the main and dip beams. The harness powers the lights from a fused link to the battery via the relays.
This is a very quick fix, I had to cut recesses in the plastic headlamp bowls to admit the cables and make a bracket to mount the relays. The Panda wing bolts are conveniently situated to secure the mounting bracket and earth tags. The rest is just plugging the sockets, connecting the live on the battery and tidying the cable runs.
This fix costs under a tenner, my Fiat main dealer's solution was a new body computer which now comes with an assistance kit (surprise) which would have cost over 800 euros fitted.