I am struggling with an IF and INDIRECT formula that is returning #NAME?

My formula is:

=IF(INDIRECT('Course Details'!B9&"!K70")<>"", INDIRECT('Course Details'!B9&"!K70"),"")

What I am trying to do is to pull in a number from K70 in the sheet that has the name that is referenced in B9 on the Course Details sheet. But if that cell is empty to leave my cell empty.



The following formulas all work okay:

=INDIRECT('Course Details'!B9&"!K70") this works fine and returns the number in the K70 cell of the sheet referred on in the Course Details cell B9.

=IF(INDIRECT('Course Details'!B9&"!K70")<>"","y","n") also works fine and returns "y" if there are numbers in K70 on the sheet referred to, and "n" if not.


But as soon as I swap out the "y" for the INDIRECT formula I get #NAME?


I have probably not noticed something that will be glaringly obvious to others - but have stared at it long and hard and can't figure out why it doesn't return a value.

Any help very gratefully accepted.