Commissario
I don't remember the exact details but it wasn't anything to do with VHF. It was something along the lines of "Take the Laser 558 frequency of 558 kHz, mix it with the Radio Kent frequency of 105.700 MHz, inject the 10.7 MHz IF and you get a carrier on coastguard channel 16 which is a potential risk to human life". I'm making up the figures because I can't recall the exact details. They said that Laser was running 50kW (it never did) and "its signal is spreading far and wide, there's absolutely no way that it can't cause interference". That's a phrase that I do recall word for word. There was no evidence backing this up and the words 'potential', 'possible', 'maybe' were bandied about a lot.
I do remember a conversation I had with one of the offshore engineers a couple of years ago where he described a situation in the 80s where North Foreland were concerned that the signal from Laser was interfering with the emergency calling and working frequency of 500 kHz. Laser turned off their transmitters and the interference was still there so Caroline turned theirs off as well but it made no difference. A while later, North Foreland called them back and told them that they'd traced it to Invicta Sound and the BBC World Service!