@viccles ...
Unfortunately, there isn't any way that I know of to remove the question numbering in Classic Quizzes or New Quizzes like you would want to see. The best suggestion I can offer is to indicate in your question stem that, even though there are two parts to the question, you indicate in some way that there are two parts. You could say, "For the next two questions, you will answer this question (part A) and the next (part B)...as they are related to each other." (or however you wanted two word it). Then, you would start out the question such as:
PART A: [write your question here]
PART B: [write your question here]
Anyway...just a suggestion...my $0.02. Hope it helps in some way.