My read is that BT communicates zero about infill, doesn't even update the availability checker with a prediction until a new cabinet is live.
Back in January, BT told Basingstoke and Deane Borough Council that they would return in the summer to add 20 more cabinets. This information never appeared in any of their rollout plans and no connected lines had availability data tagged to them. BT themselves would respond to individual queries with the generic "no plans for the next six months" answer. My cabinet was done less than two weeks ago, yet no connected lines have any availability data.
I think the problem stems from the exchange-centric approach. BT says Basingstoke is done, any infill will only be listed in the availability checker once the cabinets are active and ready for orders.
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DougM