Conditional Formatting On MATCH / LOOKUP Function?

I have an "actual build" worksheet, which allows the user to select which materials were used, material properties (e.g. material grade etc.), including its corresponding length. The user can enter all these in manually, or select the material name from a pre-defined list (Reference worksheet contains this information), and then the associated properties are automatic lookups from the Reference worksheet.

So all this is fine / completed, and the LOOKUP returns its theoretical length from the reference table. However, its actual material lengths will almost never match the theoretical length, so what I want to happen is for a conditional format to highlight the cell, to notify the user that they need to enter a manual value. The auto-looked up length is still useful a proposed build on the worksheet, but having it highlighted to ensure it is manually entered later is the objective.

The other thing is it can't just check if it's a formula, it has to check if it is a formula with a MATCH/LOOKUP function. E.g. it needs to be unhighlighted if someone has a basic formula, ie = 2*0.42 if there two of the item etc..

Hence, I was thinking of having a conditional formula that "format only cells that contain" and then format only cells with "specific text" and "containing" and "MATCH(" text function, however this doesn't seem to work.

Length cell formula:

=OFFSET('Reference- Materials'!$N$5, MATCH($BO32, Materials_Item_Number, 0), 0) * $AH32