On your way to this cache, pause outside Tanzania House and ponder this... Before the age of street-lighting how did gentlemen ever find their way home from the club on dark moonless nights on the dirty and dangerous lanes of Georgian London?
To keep themselves safe from puddles and footpads they would employ a boy carrying a flaming torch to illuminate their way home. This torch was called a "link", after the cotton or tow wick, and the boy was unsurprisingly called a "link boy". He was paid the grand sum of a farthing a time. On arrival at the gentleman's residence the flame would be doused in a large snuffer by the front door, often mounted in elaborate metal-work these were known as "link extinguishers".
Occasionally Georgian houses still retain these conical iron appendages and you will see two fine examples adorning the entrance to the Tanzanian High Commission, resplendent in gold paint - as far as I know the only gold link extinguishers in London. The south-west side of Berkeley Square, half a mile away, is also a fine area for the eager link extinguisher spotter.
Incidentally, the expression "cannot hold a candle to" (meaning "inferior to") may derive from a comparison to a link boy, which like many other useful roles was regarded as low-status position in society. If you could not hold a candle to somebody, you were not even good enough to be their link boy.
Now carry on the short distance to the cache - you'll want to be nearer to a load of nonsense rather than the eighth president... but it should be a nice easy one.
Well done to lisboa_bruno - the FTF, seemingly just minutes after publication! :-)
And also vixvixvix - STF. Sorry about the fiddly log!
TTF - kmlooi, good luck in the exam.