Eigg's Wikipedia page has a lot of information on the island.
The given co-ords are NOT where the cache is hidden; they point to a random spot in central Eigg, within 2miles/3Km of the cache's actual location. There's no need to visit the given location, so please don't! In order to find this (re)hidden 'Eigg Box', you'll need to follow the clues below...
The hum of hydro, the whirr of windmills
This is a modern place, shy of diesel bills.
They used to rely on generators but now
The smelliest thing on Eigg is a cow.
By the harbour you'll find information
On the main A00kW watery power station.
Also close, a standing stone.
A marker of this as Home.
For the folks who bought the island, fair.
To secure their place, right there.
They made this their slice of heaven
Back on June 1B, 1997.
An Sgurr is a striking rock.
Fans of Close Encounters may be reminded a lot
Of Devil's Tower in Wyoming
And be tempted to go a-roaming.
It's safe enough in good weather
To climb this C93m treasure!
(Any OS Map will give you the figure,
Or divide 1,289ft by 3.28, with vigour!)
Now head north towards your prize
By a path, you'll find it lies.
So take heart and perhaps bring a bike
To stop this one being a significant hike.
The box you'll locate with views of Rum
At N56° 55.((BxC)+A)(B+C)((CxC)-B) W006° 09.A(CxC)C - Have fun!
You'll have fine views of Beinne Buidhe and that dramatic An Sgurr
And you're not far from the famous Singing Sands, so leave time to get there!
Huge thanks to RoPeHe for relocating this cache, the Eigg Heritage Trust for permission to (re)hide it, and to Maggie Fyffe (Trust Secretary) and the community on Eigg for their help in maintaining it. I hope it brings extra visitors to their remarkable island. Be sure to see the Cathedral Cave in the south-west of the isle if you have time - just follow the the purple spots.
Other caches in the Small Isles series: Rum, Canna and Muck. And as of August 2015, another Eigg cache.