Transferring an ISA from the current tax year

[Rishi]

ISA transfers-in

I’ve filled out an ISA transfer form to transfer in to T212 for this Tax year. I’m just missing a T212 ISA account number. Should I open the T212 ISA to get the number and just not pay into it until it’s transferred ? I intended a T212 ISA from the outset this tax year but with everything going on I failed to cancel my standing order to my existing provider so have added funds this tax year.