Note: The above co-ordinates are not for the cache, but for the first stage.
The first stage takes you to the last sighting of the TARDIS, it has since materialized in another time and space, perhaps in the past, perhaps at GC4GA47. You can see previous sightings of the TARDIS in the gallery. You used to activate the TARDIS with the pass phrase "c0g t00 hack", but you'll need to employ alternate means to employ the pass phrase now. Thats it.
At the final you may want to approach from the road to the south east, especially if it is at all wet. Adjust the final coordinates by N -0.086 W -0.154 minutes to find a suitable parking spot.
I hope you enjoy the cache, but please enjoy it in moderation.