What I would say about Ashbourne though, is that, in my experience, many residents wouldn't like 'outsiders' telling them what to do, particularly from other cities and especially from further a field. As is the way of some towns/villages in the countryside, regardless of the issue and that, as a traditional place, there would be a general resistance to change, no matter what.
That said, this debate does raise some interesting issues:
I find it interesting that so little is known about the historical context of the head. Particularly when people wish to see it kept on the basis of historical interest.
I had been dubious about the nice little black boy story and Sir Walter Raleigh. However, having read up on it, Sir Walter Raleigh did have connections to the town and apparently owned land there. He did indeed live with/was accompanied by a black man/family and that there were black people living and employed in the UK during Tudor times. So, that story does have some credence. But, assuming that there was a black boy and that the locals were affectionate towards him, the depiction of him nevertheless belongs to a different time. I can understand the resistance to sudden change by a group of 'outsiders' to local monuments that people had become accustomed to. But on the other hand, I think that towns/councils and or parliament should have legislated for their relocation to museums some time ago. I think that people should consider whether they attach genuine importance to some of these objects and whether that outweighs the potential upset/hurt/feelings of disrespect that they may cause to others.