LD8 is two adjacent data centres linked together by cross-connects. 7/8 Harbour Exchange belonged to Telecity, who subsequently acquired Redbus, the operator of the adjacent data centre 6/7 Harbour Exchange. Telecity was itself acquired by Equinix subsequently.
The two data centres that make up LD8 are similar but different. For example they have different power systems, cooling, power levels etc, so we feel it makes far more sense to treat them as two separate data centres, rather than as one.