I had done exactly the same as you brendan. I also took the wrong letter off the two word indication to 29a, i.e. my extra letter was coming from the second word and it is obviously the first word. I now have a message that nearly makes sense, as I now need to work on the penultimate word to it. I knew the meaning of the first word as I spent 42 years as a Stress Engineer on later versions of the thematic entries.