Speaking as an ex-employee of Centrinet....
For starters, Kelly is not the technical guru at Centrinet; that would be Chris Brown - who really should have been the one making this announcement.
Any network tech worth their salt can work out that their primary IP allocation is being advertised by BT's own AS (2856) and therefore, Smartbunker is not appropriately multi-homed via different transit providers and are not suitable for mission-critical applications - their website only claims connectivity through BTnet.
I also find the claim that BT dug up 11km of roads to put fibre in as absurd; I live within 10 miles of Smartbunker and would have personally witnessed the chaos that this would have caused - plus, as Kelly quite rightly points out, there was 'comms ducting' already in place and BT have re-used all of their existing underground ducting throughout the UK to lay a fibre backbone - BT would have re-used that existing ducting or taken a feed off the nearest conduit in the area that already carried fibre - no way would BT dig up 11km of Lincolnshire roads!
The fibre end-to-end may be 11km but there certainly wouldn't have been 11km of roadworks.