Hi,
If you meet the condtions at
EIM13700 - Termination payments and benefits: section 401 ITEPA 2003: foreign service: reduction of charge, this can still be claimed.
The foreign employment, whether the relief is due or not, should still be included on a UK employment page in order for the income to be included on your calculation.
You do not show any tax deducted on this page as it is claimed as foreign tax credit relief where appliable.
This then allows the claim for the 30k exemption to be applied, if applicable.
Thank you.