leasing/managed offices in London, UK with 10gbe carriers POPs?

Hi, I was going through this database[1] looking for office facilities/buildings with 10gbe carriers POPs already present, but only datacentres are listed. My requirement is low cost 10gbe connectivity to any London datacentre where I could either get either low-cost few racks hosting+partial transit.. Well multiple 1gig links might be ok too. I am sure there are already large office blocks with multiple 10gbe carrier POPs or am I? Maybe it is possible to save costs and time by choosing office with built-in good connectivity rather than wait months and multiple permits to dig the road etc..? [1] https://www.peeringdb.com/private/facility_list.php Thanks,