I've looked into a similar issue on my wife's Honda Jazz. The fuel filter is inside the tank. To do anything with it involves a hugely complex procedure to even access the tank (due to it being under the driver's seat on this car) and it appears to be something to leave for the life of the car or until a fuelling issue arises.
I suspect that the same applies to the Panda.
Previously, I've been used to running cars with in-line fuel filters that can be changed relatively easily and appear on the service schedule.
I suspect that these are becoming extinct, probably in part as car manufacturers want their service schedules to appear less complex and cheaper. Maybe fuel in the UK is clean enough now for a filter to last the lifetime of the car.