But presumably an 'ardent Brexiteer' by definition will have already weighed up what they think are the likely outcomes and decided that on balance leaving the EU is worthwhile, and that's why they voted to Leave in the referendum. That is, an 'ardent Brexiteer' doesn't want to leave the EU because 'it would be bad to go against a referendum vote', they wanted to leave the EU on the merits of the question, and would still want to leave it even if the vote had gone the other way.

The person you want to address your question to is not an 'ardent Brexiteer' but rather someone who was either neutral on the question or who voted Remain, but who now thinks we should leave because it is more important to follow a referendum vote, even one they don't personally disagree with.