The public BT Wholesale Checker will only report status on lines, most accurately by entering a phone number. It is possible to use this to determine which cabinets are active only if you have a number of a line connected to the cabinet you want to check.
The raw cabinet data is not publicly available, although versions have been leaked online. End-users tend to have most success getting more detail by enquiring with a friendly FTTC ISP (ADSL24, IDNet, AAISP, etc).
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DougM