PN
Gee in the Varsity was a rapid fixing aid!
Gee 2 about a 6 minute exercise except when pretend flying a "supersonic" Canberra in the D.R. sweat box where eventually your pencil was outpaced. However this seasoned one such that a 3 minute cycle was easy with Gee 3. In fact once I managed a 2 minute cycle for the length of England.
binbrook
AFAIR the upper limit of UK airways in the 50s was something like 12000ft, not that we had the nav kit to use them.
I thought it was 10 thou but I'll accept 12 but early '58 it became 15000ft'. With this came FLs and all the other gubbins upwards and above FL 290.