Just for a bit of context, here's a list of all the football grounds in London ranked by capacity.
When stating your wild fantasy for which ground Harlequins - or a club renamed to suit your whim - should move to please refer to this list first:
Wembley (90,000)
Emirates (60,000)
Stamford Bridge (42,000)
White Hart Lane (36,000)
Upton Park (35,000)
Selhurst Park (29,000)
The Valley (27,000)
Craven Cottage (25,700)
New Den Stadium (20,000)
Loftus Road (18,000)
Griffin Park (12,000)
Brisbane Road (Leyton Orient) (9,000)
Church Road (Hayes & Yeading FC) (6,500)
Victoria Road (Dagenham) (6,000)
Underhill (Barnet) (5.900)
And for the more whimsical amongst you:
Majedski (24,000)
Stadium MK (22,000)
Vicarage Road (19,000)
Kassam (12,500)