Money in help to buy ISA with overdraft in current account

I have around £1800 and I'm currently unemployed but I want to open a help to buy ISA with Barclays before the closing date. I would also like to take advantage of the larger savings allowance upon opening and put £1000 in to start me off. However this will only leave me with £800 to live on but I have a £2000 arranged overdraft as part of my Santander graduate account. I'm looking for work and a new room to rent so imagine I could end up in about 1k of overdraft before my first payslip comes.

My question is whether it would be acceptable to have £1000 in a help to buy ISA with Barclays while I am in my overdraft with Santander? I am confident I will get myself out of the overdraft within a month or two and it would mean I have made a good start to the account and can start putting in £200 of my wages monthly.