In May, 1975 I went from Zambia via South Africa to Rhodesia to do some research at the National Archives in Salisbury in the plush outer suburb of Borrowdale. Salisbury was only a few hours drive from Lusaka where I was living, but these were the days of UDI. In 1965, the self-governing colony of Rhodesia had made a Unilateral Declaration of Independence from the UK rather than entertain the prospect of African majority rule. The border between Zambia and Rhodesia had been closed at the end of 1973. Travellers’ cheques issued in Zambia were stamped “negotiable anywhere in the…