I had a spare aluminium case with adjustable padded dividers in it that is now not spare any more

. I bought 2 of them while they were cheap at Bunnings... just as well now

.
Be wary about the perception of value Phil

... I'm starting to. $30 here, $50 there...
Just for info, if anyone else damages their lens and decides to replace it... I found the other day that the focal position of the replacement lens I got is closer to the lens than the original genuine
GoPro Lens. Its the same focal length but the focal plane is not in the same position. No biggie while its out of the housing, but in the housing at wide FOV I get a full circular vignette in photo mode and partial vignette each end of the frame on wide video.
All is OK at medium FOV though, it just means I can't make full use of the CCD when the camera is in the housing.

So make sure you get a lens cap and use it!
Al.