Better late than never, welcome to the forum Rarr! I'd say Joe is getting better known here (England AND Scotland), but I guess its up to people like us to make him better known, which it looks like you are doing.
it's_all_about_apples, you make a good point, however unlike Mayer, White Stripes etc, Joe's albums are akways found in the blues (or worse speciality) section in the record stores. That seems to be the case with all artists on labels such as Provogue and Ruff, which is kind of frustrating as it means people are missing out on this kind of music.
However as far as chart positions go, if Joe's album is the tenth highest selling in one week, it will show as no. 10 in the "pop" chart as there is very little coverage of any specialist charts in this country (other than perhaps classical).
"The recently formed Edinburgh Blues Club has identified an appetite for the personal communication between musicians and audience that the blues long ago perfected." The Herald Newspaper (Scotland)
http://www.edinburgh-blues.uk