Cannot make SA payment plan online

Hi, My SA for 2023-24 was submitted and received on 7th March 2025. The final bill was around £500. Hoping to set up a payment plan online, but when I follow the instructions to do so I'm asked to file my self assessment, which I've already done. My question - does it take a few days for the payment plan option to become available after submitting? Thanks

Hi ,
 

It could be that you haven't fully submitted your 23/24 Self Assessment return online. Log back into where you completed your return online, and check that you have fully submitted the return to us. If you have, contact us by webchat or phone via : Self Assessment: general enquiries to allow us to investigate further, and give you more advice on setting up a payment plan. Thank you .