Mini Filter or no
Well in order to put this to bed, have just been out and had a tinker with the Mrs motor, and yes indeed there is a mini filter in the banjo bolt, it is quite a course gauze, so what it's purpose is I can only guess, paper filters breaking up is not very likely in my opinion, fuel filters have been made of paper for as long as I can remember, and if a batch got out that broke up they would be recalled, it would not be up to the vehicle manufacturer to introduce an after filter filter, more importantly there is a restrictor orifice in the return banjo, some have filters this one does not, it does however have a variable restriction ability due to the piston inside, I seem to remember we had the same set up on Alex motor and think we did a full photo shoot of all the bits and how they work so not going to repeat it here, and I do not want to alter this one as it is the best performing TDi I have ever driven, this pic is of the two orifices