Hi,
They will lend you the full amount and they advise you to start the loan application 2 months before you head out to FTE.
You may have difficulty because the house you are lending against has no mortgage (one of my friends was in the same situation)
You don't need to show them a business plan as they are very familiar with FTE and the setup with regards to the amount of money and timescales etc.
I advise you to ring them as they are very helpful!
Martyn.