Unfortunately, I suspect the problem may lie with Nimbus who have a poor reputation for courtesy.
Although I think that the problem with Lyrita/Nimbus goes deeper than that (a suspicion shared by the Grace Williams Society) the issue of non-response to emails or letters has been mentioned before.
These small labels need every ounce of support they can get to survive. On this site-as members will be only too aware-we try to protect their cds from free download :). Those of us who love British music buy the cds produced by Lyrita and Dutton (not to mention other such labels). Those interested in the more obscure or neglected corners of the repertoire buy the products of labels like CPO. Without our support these companies would go under.
And yet they either cannot be bothered to respond to messages from their customers or (as in a recent case involving Dutton) reply with extraordinary rudeness. Are the people who run these companies completely unaware of the need to keep their very small customer-base at the very least properly informed?
