@lupyuen isn't it trivial to monitor the airwaves with basic equipment, and work out from this the callsign of the balloon (which would surely confirm it is legit?)

UK only forbids the transmissions as its a small country, and a defective/misconfigured TX up in the air is going to cause a lot of hassle with interference due to the range it can cover (and UHF ham frequencies are very near such things as RF keyfobs for opening/closing car doors or even starting vehicles)