Agree, I'm not sure what made this one so difficult, and yet it was.
Well analysing my own attempt.
I started off looking at the fish but I could see five possibilities so I did heat sources and got that one straight away.
Then I did the baseball, but put "walk" in instead of "safe". Realising there were five baseball terms, I returned to fish and got two wrong combinations.
Then I went back to baseball and realised that "walk" could be eliminated if it was baseball
calls.
After that, I still had five fish but realised I had several words that don't sound the way they are spelled. It took me a little while to convince myself that the "l" in "walk" is silent, but after that it was plain sailing.