After 2 1/2 years of searching, I'm a very persistent person, I'm now holding a 1913 copy of North and Hillard's Latin Prose Composition - a classic! I ordered it from overseas and it arrived today after about 5 weeks of waiting.
I'm going to get this posted ASAP. Sorry, still looking for the key. The keys are almost impossible to find. Should anyone be near a good college library, and you're in the mood to do some photocopying, please have a look-see for the key. I'm looking for the Key to North and Hillard's Latin Prose Composition For the Middle Forms of Schools. It'll need to be printed before 1923 and the publisher will be Rivingtons.