First off, mate, welcome to ECN.
Enjoy your stay here and please use this site as much as possible, there are some terrific resources here for people such as yourself.
One example would be the Tech Reference Area, Scott35 has done a brilliant job of getting all of the technical diagrams and what-not in one simple area.
Please, don't ever be afraid to ask questions, the dumbest question is the one that is never asked at all.
On to your original question.
Most of us here have been through some sort of an apprenticeship, getting one in the first place was one of the hardest things I have done, to be honest.
At the age of 27, you are still young, but considering that you come from a background of banking,(unless you are doing so at the moment), I would recommend that you get some real exercise, bending and stretching.
Pulling muscles and ligaments on your first day would not be a good look at all.
Jimmy (wire-twister) makes a very under-stated point in his post.
Don't do your time with an electrical shark, at the end of the day, you are only as good as your practical skills taught to you.
If the guy that teaches you is rough in his "workmanship", that will rub off on you as well.
It's strange how this happens, but as an apprentice, you often don't know any better or don't have the priviledge of being able to argue the point.
I'm sure most of us picked up the odd bad habit from those that trained us, but we only found out that these things were wrong, after the end of our time, when we were exposed to the wants and needs of an Inspector.
I wish you the best of luck, mate, if you want to take a leap like this, all the best.
Learn all you can, to some "electricians", it's just a pay check, the folks that participate in this Forum are always trying to improve themselves.
I remember an elderly electrician told me once always try and be the most technically correct tradesman that you can ever be, anything less, get your gloves on to start washing dishes