Hi Louise Tai,
No, you will be able to amend your tax return to include the Foreign Tax Credit.
You can either log in to your online tax return and amend it from there, or write to:
H.M. Revenue and Customs
Self Assessment
BX9 1AS
Advising of the changes to be made, or by submitting an amended SA106 foreign supplementary page.
Self Assessment: Foreign (SA106)
Thank you.