As said before, there are 2 separate issues here. The Hunting ban- and the large number of foxes in uk towns. For the second, as said before- and back by long-term and rigorous research by the University of Bristol, foxes are very good at regulating their numbers in face of the amount of food available.
Those who feed urban foxes, however well intentioned, must stop, or they are signing their death warrant. And those who drop litter and leave food litter all over our towns, be it McDonalds or open bins at the back for restaurants, gardens or in the street, must be stopped too.
When food is plentyful, all vixens will breed and have several cubs. As soon as the food source becomes limited, only the strongest vixens will breed and have 1 or 2 cubs max. Simple and proven.