Slow Fuelling Issue
 

Ok so after spending about 20 mins forcing 15 litres of diesel in to the car I need to know if there is a fix for this - much searching here and google suggests the charcoal filter needs to be changed?

Charcoal filter is common fault on petrols only. Diesel it's more the angle of the nozzle. Try no putting it in all the way works for me.

Ah I see, resorted to putting it virtually upside down! Is there a reason for this issue or a fix?

No fix some stations are better then others you just find a way that works for you and stick with it.