In some countries, people operate beacons to study radio propagation without needing a licence in the ISM bands. In the UK, such operation is unclear, so I have asked OFCOM to clarify. As I only asked yesterday I am not expecting an answer soon.
My question was:
"May I legally operate a test beacon, to investigate radio propagation, without a licence in the ISM bands at low power? If legal, at what power?"
Whatever the answer, I shall post it here.
In the meantime, this link seems to give a fair summary of legal ISM operation.
My reading indicates that at 8m one can use 10mW ERP legally under the short range devices legislation without a licence, but I do not know about type approvals. Can none type approved gear be used without a licence in the ISM bands in the UK?