Another example of lazy and sloppy reporting, trying to impart fear and panic for no reason other than to get a headline.
Radon itself has a relative short half life, and mostly emits alpha and beta particles which are only a hazard to people if you get too close. Radon particles attaching themselves to dust particles and then being inhaled are the biggest risk to humans.
Having a level "134 times greater than the UK’s recommended “safe” level" is meaningless as difference between the "safe" level and the "dangerous" level is many orders of magnitude, so being 134 times over the safe limit is probably less exposure than you would get walking down Union Street in Aberdeen.
I once visited Doureay visitor centre, a very interesting trip and as it was mid week there was three of us on the tour, and one of them was the guide. She would give us the standard spiel and then we would have a chat about various things fr five minutes before moving to the next location. Dounreay was at the time the storage facility for rock core samples from all over the UK, and on one occasion all the radiation alarms went off which would normally signify a major breach but in this case it was a granite core sample from Cornwall arriving at the stores.