When I was dealing with the management of a Director's Loan Account a few years ago I used to make sure that the account never went more than
5k in deficit, I think to avoid the creation of a beneficial loan.
Looking at current HMRC guidance I can't find any reference to the 5k limit, have things changed?:
formatting link
I note the requirement to ensure that any deficit is made up no later than 9 months after the year end.