This p45 stuff is really confusing me

So is it FROM a particular date in April? I have never come across this before, I THOUGHT it is your total earnings with an employer?
My other post was confusing but here it is: my p60 appears to be total earnings with these people. (ie not the total earnings for the whole year, presumably because they lost my p45 initially).
My p45, I THOUGHT, would be the total earnings for the employers, so the figure should MATCH that given with the total earnings with them on the p60? However, the p45 figure is ~ 1/10th that of the p60.
I am just getting impatient as I require my rebate which I have been waiting for these lot and last years employers. So I guess if I give the tax office my p60 and this (probably incorrect p45), they will still accurately calculate my refund.
Anyway, I am still waiting to hear from the chief exec who is looking into this and other issues, and they have confirmed receipt of my letter.