Personally, I don't think incendiaries would change the British response. The Luftwaffe dropped incendiaries over London during the Blitz, and other cities, and although Coventry was pretty bad I don't think it changed anything significant in RAF operations. Hell, the RAF was firebombing German cities much more thoroughly than a handful of V-1s could manage, deliberately creating firestorms, and that didn't shift the German response to the raids. The RAF was already attacking V-1 launch sites as soon as they were identified, so I don't really see much scope for change.If they were just using high explosive warheads, maybe it would be tolerated. But what if they used incendiary warheads to firebomb London? Surely every ground attack aircraft of the RAF would be tied up trying to suppress the launch area.
But this is an area I don't know much about, so if others know more I'm happy to be educated.