"Surely an IT manager should know the difference between Word and Excel?"
Why should there be a difference ?
<whiny nasal IT voice>Well you might be CEO/CFO/CTO because you're an expert in the field and make money for the business. But you see you clicked to embed this table as an active-x direct-wibble object rather than an in-line OLE direct-fooble object, so you can no longer do Excel stuff in it when you're not in Office365 inside our cloud infrastructural nodal-thingy