grammatical number - "It’s much more than our names that {makes/make} us..."

Hopefully someone on here will be able to help me resolve a language (grammar) question that came up at work today.

Which of the two sentences below is correct?

1. It’s much more than our names that makes us stand out.


2. It’s much more than our names that make us stand out.

I think the first one is correct as I believe that 'our names' is effectively treated as a singular concept and therefore makes (the singular verb) is the right choice. This caused some debate in the office though!

A definitive answer on this would be fantastic. Many thanks in advance for your help.