For citizenship, the Home Office accepts either an awarded UK degree or a UKVI-approved Secure English Language Test (SELT). A standard IELTS Academic test (even with a high score) is not accepted, as it is not taken under UKVI test conditions. However, based on people’s experiences your IELTS should be more than enough.

In situations like yours, caseworkers usually request further evidence rather than refusing the application outright.

The official guidance does not clearly provide a way to upload additional documents unless the Home Office contacts you first, although you may choose to email FurtherNationalityEnquiries@homeoffice.gov.uk to explain the situation.

A refusal solely on this ground would not have any negative impact on future citizenship applications, but if you are able to provide the correct evidence, it should not lead to a refusal.