Ok, sorry to be annoying, but worried I've done it wrong now.
If E.S.R. = 118.74
I = 1.374*10^-6
A = 2.199*10^-3
Then the equation is Le = 118.74*sqrt(1.374*10^-6)/(2.199*10^-3)
Which equals 2.968m?
Also, sorry if I've written that equation terribly.