Dsc, I think there is no shame in giving up! I couldn’t believe it when I read the preamble and saw that several long entries were not only unclued but also encoded, while some other entries intersecting those unclued entries were jumbles! A denial of all the things that make solving crosswords an enjoyable and satisfying experience. On the other hand I must admit that solving those down clues with missing ‘letters’ was worth the (not inconsiderable) effort.