I think the integrated air defence system which Dowding put together of radar, observers, resilient comms and centralised battle management was the key not just any part of it. Remarkably far sighted and un-British , presumably why he was sacked as soon as the threat passed.
Not sure how it resembled the internet in any way other than resilience through redundancy which is pretty much a feature of all types of critical application telecom networks.
Did Bletchley play any part in BoB, I have not really ever seen any reference to it , was it too early in the war or was the Bletchley operation focused solely on the Atlantic , I assume the Luftwaffe had an enigma variation !