This leaked out at the time, and even appeared in one of the newspapers, probably the Telegraph.
After the war I can remember asking some of the chaps from Yeovilton about it and being met with amazement that I knew, and also being told to keep my mouth shut as it was "secret". Pity no-one told the papers.....
And the guys story was that the lazers WERE used on at least one occasion - against Skyhawks.
I can even remember a photo that was reputed to be the device - a kind of dalek shaped/sized housing with an optical panel in it. Whether that really was the device is another matter.....