The Quest

Fabian and I have returned from our camping holiday in darkest South Wales. A bit of spelunking, a bit of getting away from it all, a bit of hiking, and a lot of ancient woodlands and picturesque ruins.

Even a few of the Welsh were there, if you can believe it!

What did we miss?

[Warded to McGonagal and the Brothers Prewett]

Headmistress,

Fabian and I have found that our improvised method of map-dowsing was successful. It allowed us to locate Bangor Tewdws, which, when we announce the finding, will be the foremost discovery of magical archaeology of the 21st century. You may need to give us endowed chairs in archaeology and establish Hogwarts' claim to the site through us to keep it from getting ruined. Fabian will probably want to negotiate terms with you.

On a very practical note, the method we've got will be ideal for finding the horcruxes, but we'll need three things.
1: a related artifact to use as the dowsing focus
2: a large scale map
3: a high-ceilinged greatroom in which to spread the map.

Can we ask you for the loan of the Hogwarts commons and the Sword of Godric Griffyndor? We will give them back when we're done.