Thanks to Richard Hill for the following update (and for organising the recent monitoring exercise):
Attached is a spreadsheet including the latest sampling for the South Wales cave venues.
I have added the data into the BCA spreadsheet which will be updated on the BCA site soon I hope: https://british-caving.org.uk/?s=radon
You should by now be using this data to log your radon dosage. Radon Underground is going to be updated too and the tables will be updated with this data included.
Thank you to all who contributed to the sampling.