Do you have to put in £500 as a one lump sum or as long as you’re putting in £500 every 4 months the overdraft remains available?
In theory, it doesn't have to be one lump sum but you must also satisfy the following conditions:
The account must be used as your main or primary current account.
Your main form of funding, for example your student loan, grants, parental contribution, and/or income from any employment, must be paid into it. If you don’t regularly pay in your main form of funding, we may discontinue some of the services offered on your account or close your account.