British citizen to work abroad for UK company long term

I have been regularly visiting the USA for work on ESTA for the past 18 months. I have spent quite a considerable amount of that 18 months in the USA (no more than 3 month stints, visiting the UK for a short break before returning to the USA)

My job is an IT-based "special skill" and requires regular visits to customer sites. The UK-based company that I work for would like to move me there, which I have tentatively accepted.

What are the steps to achieve this? My situation is a bit different to the usual since it won't be a US company that employs me. There are clients in the USA that could vouch for me, however.

I would be looking at an initial duration of one year.

I am a graduate with a Bachelors degree (Hons)

Many thanks in advance.