The following is a link from the Early Music Journal. It records on its contents page at the bottom the passing of DM...and makes the claim that he found his excellent, and well referenced book was such a struggle to write that he vowed not to write again....though he would have probably done so...
http://www.jstor.org/pss/3125677There is also reference to his American Tour where ofcourse he was becoming very popular with his showbiz personality that yanks love. Also, I recall from the RAM collection catalogue that there was possibly a programme entitled The Music of the Americas? Does a recording of this exist, and what exactly did it consist of? I remember Jordi Savall, and no doubt others did something similiar..
PS. Apparently, the ITV Early Musical Instruments series was to be originally called What Should They All Sound Like?...a rather odd but deliberately mysterious title.