Can't see drop down list in Excel VBA

I've created a very simple drop down list in excel. It holds a sequence of integers loaded from a cell range (years). I need to read the selected value in vba. However I can't even seem to find the control!

I've tried

CboYear

Sheet2.CboYear
Worksheets("SheetName").CboYear

etc. etc.

From everywhere in VBA this control just doesn't exist. All the tutorials I find seem to assume that using just the control name will work.

I've tried the code in the sheet itself, the workbook, and a module, no luck.