Hi,
If you are providing a service to an overseas company which is outside the scope of VAT then any other expenses billed to the overseas company should be billed at the same rate of VAT as a single supply and so would also be outside the scope of VAT.
If you are billing a UK company for a supply of services overseas then it is important to work out who is your customer for this supply, as the place of belonging of the customer will determine whether or not you have to charge VAT.
If the customer is in the UK then VAT would be charged on the supply, expenses and so on. You can see the guidance below:
The place of supply rules for services
Place of belonging
Thank you.