Pip, the view that the term "chav" is derived from the Romany "chavi" (= boy) is not universally held. "Pikey" denotes something different from Romany, too, and for some time was a term the Romany used to insult non-Romany travelling people.   

As to your defence of Les:

1. That is not the point. Are those of you correctly uneasy or offended?

2. So what?

Ruth, thank you for that information. Clearly the word then is (as a matter of timing) likely to derive from the reference to "nigger minstrel" shows. In today's context it should not be used. Does that unfortunate use illuminate whether the blacking up was a reflection of "nigger minstrel" shows, or a reflection of earlier guising?

It creates a suspicion. But suspicion is not enough. It still remains possible that blacking up predates such shows, and indeed it seems quite probable that it was present in Anglian molly before Sharp's relevant words and so quite possibly before common minstrelsy.

If it was not, then it can most probably only have arisen in response to minstrelsy and so is likely tainted.

So, I repeat, is there evidence of pre-minstrelsy blackface tradition either in East Anglia or the borders? I have always understood that there was.