Arqiva. Owned by an Australian investment bank. They also own the old IBA transmission network that broadcasts ITV/C4 and co-owns the Freeview service. I.E. They hold a monopoly on TV and radio transmission in the UK. Plus with the roll-out of 4/5G mobile all those hilltop sites are making them a fortune for providing microwave relay feeds for data services.

RTÉ still owns their network as 2rn Ltd (the callsign of Irelands first radio station - phonetically 'To Erin') and they are making decent money from providing the same mobile services. Making the BBC sell off their transmission network was shortsighted.

I'm a radio and love all this. The head engineer of 2rn is a member of my radio club - he really knows his stuff.