If you want to do it properly you need to setup an inter-company loan agreement, transfer pricing, you need accountants and tax specialists for both UK and US,

If you want to do it properly you need to setup an inter-company loan agreement, transfer pricing, you need accountants and tax specialists for both UK and US, ... so the costs will definitely be significant. I don't think there are any shortcuts. Ideally, you find an accountant that is familiar with this setup.