When you are at the listed coordinates, you will see a certain number of Gods and Maids. As part of this information you will see another word (twice). Press the button nearby to hear a certain number of this word – count them!
Using the three numbers you now have, assume the N51 17 and E 0 18 and perform the following calculation on the decimal parts to get the final coordinates:
N: listed + (2 x Maids)
E: listed + (4 x Gods) + (number of sounds) - (5 x Maids)
Watch out for muggles at the final location, it's a busy area.
You can check your answers for this puzzle on GeoChecker.com.