Yes please proceed with the UK Tax position.
In answer to your questions:
We're a website development agency, so the employee will be a developer working on prescribed work/projects/tasks set by us.
He won't be employed by any other company, he would be our employee but based in Australia at 37.5 hours a week. So no seeking own clients/sales and no profit and loss made.
In the short term he would likely use his own (computer) equipment but medium longer term we would provide (assuming tax implications wouldn't be an issue with this)
All duties carried out in Australia - if he ever did return to the UK it would be vacation to see his family.
The above is obviously if we went down the employee route versus contracting.
Brilliant, thanks very much