I have downloaded the DNG converter, I'll have to copy them across to LR too because as of today, they aren't showing.
However while in LR I removed all the unwanted Pentax profiles so there is no need to scroll through that long list anymore. Next step will be to remove all the non-Pentax camera brands. Note: they haven't been deleted, just moved to a new sub-directory where LR can't find them, but I can.
The other thing I did was to enable the in-camera lens profiles. Pretty happy with the lack of distortion at 15mm here:
(Enlighten, National Portrait Gallery last night)