PaulS:
Which of those ino files is supposed to contain the FloatToString function?
in FloatTostring.h. I provided the code to show all the other functions which don't need includes. That code compiles without errors.
But I've since succeeded in transferring it from the h file into zzMisc.ino so it compiles without errors also (new ZIP attached below). Now FloatToString function works without need for any include statement, same as all the other functions in the sketch. Excellent thanks again PaulS.