I have been asked to set up a Directors Loan account as a bank account in Sage. Will I need to change the default layout for the accounts if I am using either 1230 or 1240 nominal and how would I do that if it is necessary.
You shouldn't need to change anything really as it's not a real bank account as such. It will just be to register the debits and credits of the directors loans. 1230 is usually petty cash and 1240 is credit cards, you may wish to set a new one up called 1201 or anything between 1200 and the next account just incase you need to use petty cash/credit cards accounts as well.
As the bank accounts are already "floating" balance sheet accounts they will show correctly on reports and in the correct place on the chart of accounts so you shouldn't need to change anything at all about the chart of accounts to accommodate doing it this way. The only thing is that on your Balance Sheet they will show in the Cash at Bank and In Hand or Overdraft section rather than in the correct asset or liability section.
There is already a directors loan account in Sage which will show in the correct place so I'd question why to set it up as a bank account rather than using the existing code...