A bit of a tangent, but I looks at your link to Bernard. Aren't there a lot of broken link-checking services out there already? Curious to learn what your USP is, and/or your approach to competing in a saturated market.
I've seen that happen countless times, and no service I've tested was able to monitor for that use case satisfactorily and/or at that price point.
In other words, my goal is to create a service to uphold Berners-Lee's "cool URIs don't change" mantra.