Hugh
There were 57888 appeals in London last year, of which 47% of the appeals were allowed. There are no figures for say emergency vehicles or other exemptions in that, there may be none, if they are withdrawn by the council, there may be a lot.
Thats not 60% though, I doubt 57888 is a very big % of the tickets issued.
of those, for LBR, only had 397, 35% were allowed. A long way under the average for London. If the rules were as complex as you say, and as flawed as you say, you'd expect that number to be higher.