Based on the limited information provided you will need to ensure the company doesn’t become resident under the domestic law of your new country of residence.
If it does, you will need to consider the Double Taxation Treaty in place between the UK and that country to determine where the company is resident for treaty purposes.
The treaties can be accessed on our website at Tax treaties
Assuming the company doesn’t become resident under the domestic law of your new country of residence, the company will remain solely resident in the UK by virtue of its incorporation in the UK.
This is on the basis that taxing rights of the company's worldwide profits are retained in the UK unless the company trades through a branch elsewhere.
The company can continue to pay you dividends and a salary, but the taxation of these will depend on where you personally are tax resident.
Again you would need to consult the relevant Double Taxation Treaty with the UK to determine this.
Aside from this I cannot comment on matters relating to personal tax, you will need to contact Self Assessment and PAYE directly.