Yes, there should be. It's a positive declarative question - the kind that has an epistemic bias towards a positive answer. The bias is reinforced by the inclusion of "surely" , which indicates confidence in the truth of the proposition. So, yes, I'd add a question mark.

Can you start a question with surely?

We can use surely, especially in negative question forms, to show surprise: Surely you're not going to take two weeks off work? (I am surprised that you're going to take two weeks off.) Surely she's not interested in a job like that? (I am surprised that she is interested in a job like that.)

Are question marks necessary?

Just because you use the word “ask” in a sentence doesn't mean the sentence should end with a question mark. You shouldn't use a question mark because you aren't asking the question; you are requesting that someone else ask the question. ...