After filling my tdi with unleaded

Have done similar with a diesel.

As long as you’ve not driven any distance, you may get away with it. Call a garage/breakdown, they will tow you to a garage, drain the tank and flush the lines. Takes about an hour/90 minutes.

Cost wise, think it was about £150 plus a gallon of diesel.

Don’t drive/start the car until it’s flushed!

Yes, with a 2005 clio dci, as long as you really haven't driven more than a couple of hundred yards the mix won't have got far into the system. I got away with just a good drain down of the tank and then brimmed it with diesel. We kept the diesel/petrol mix that we drained in a big plastic drum and then added it a couple or three litres at a time to brimmed tanks of diesel in the clio and my 1.9 pd passat, it took a while to get through it all but both the cars ran fine. There was even a section in the clio handbook that said you could add 5% petrol to the diesel without harm to stop waxing in winter.

Used to put a couple of gallons of petrol into our trucks in the winter (before anti-waxing fuels were invented). Saved having to light a fire under the fuel tank!