Gear ratio effect on stopping/skidding

It is, to be honest, sheer bloody-mindedness that has seen me keeping that gear- I always used to rock around on 48/18.

In a way it's a nice challenge trying to control the bike with a bigish GI, especially as I am really just learning to skid etc- my theory is that if I learn on this then anything else will be easy.

Yeah but trying to continually skid/skip stop/whatever on that kind of GI is going to be really really harsh on your knees, you only get one set of knees!

A drop to 66-68GI will allow you to still hit close to 30mph relatively comfortably, but still give you so much more bike control than you have now, making stopping etc require far less effort.