Not sure if this is common knowledge (I only found out through an English colleague) but you can find out whether you should pay tax as a visitor or resident if you check online at Click on your situation then 'Travelling/International' then 'Are You A Resident For Tax Purposes'.

The tax form I completed at the recruitment agency led me to believe I was a visitor, so I'll have to submit a new form. This also means you will complete an income tax return annually.

Hope this helps someone!