Whilst filming the Bodmin video, the facts are already being overlaid, despite the fact they said it'd be done in post production.
Gus says that "Kernow" is the name for Cornwall in Cornu-English, i.e. the English dialect of Cornwall. In fact it comes from Cornish, which is a separate Celtic language and not a form of English.
When they are talking about how big the 'cat' is, they use the measurement in 'feet'. It seems that English cable installers would use the metric system to measure something they saw, even a 'cat'. So they should be using meters, not 'feet'.