Stealth will be required as this is in a high muggle area, right next to houses and a fairly busy park.
You are looking for a green bison tube hidden on the corner of a street named after a well know British Poet who was poet laureate from 1850 to 1892 - much of Queen Victora's reign. She was an ardent admirer of this poet's work and he was given a peerage in 1883.
One of his poems appeared as a song in the 2004 film Vanity Fair, sung by the character Becky Sharp:
Now Sleeps the Crimson Petal
Now sleeps the crimson petal, now the white;
Nor waves the cypress in the palace walk;
Nor winks the gold fin in the porphyry font:
The firefly wakens: waken thou with me.
Now droops the milkwhite peacock like a ghost,
And like a ghost she glimmers on to me.
Now lies the Earth all Danaë to the stars,
And all thy heart lies open unto me.
Now slides the silent meteor on, and leaves
A shining furrow, as thy thoughts in me.
Now folds the lily all her sweetness up,
And slips into the bosom of the lake:
So fold thyself, my dearest, thou, and slip
Into my bosom and be lost in me.