The cartridge is called Das Haus vom Nikolaus and was created by espe2310.
This is a "play anywhere" game that has been used for a number of different caches, including Remember Christmas by BaSHful in Dorking. There is more than sufficient space to play it on Rectory Meadow, at the above co-ordinates, or you can play it on any open space of your choosing.
It is based on the old German children's game of drawing the house of Santa Claus in one stroke without duplicating any lines. It has been run on a number of platforms, so it should be bug free for you. When you complete the game you will be given a 10 digit number, ABCDEFGHIJ.
The cache, a suitably festive Christmas Tree, is hidden at:
N51 AH. F-G H-A I+J
E0 CD. A+F B+C E-G
A couple of things to be aware of:-
The setup of the game requires you to define points "A" and "B". Remember that by the time you have done this you will have walked from "A" to "B" and do not need to walk this line again.
If you make a mistake you are asked to start afresh. This means you must completely exit the game without saving and restart with the setup bit.