Is this employment as well as being self employed?

I'm a freelancer registered as a sole trader. I've just gained a new client that is a university, they have a LOT of bureaucracy to get approved to provide services, have a set hourly rate they would pay people and importantly, deduct tax at source. Does this count as being employed in some way? They've pretty much refused to pay me without deducting the tax so that I can do it myself. If so, how easy is it to include this on a self assessment without being taxed a second time on however much the university pays me?

Hi

This is employment under PAYE and you would declare this on your Self Assessment tax return as this.
You show both the gross income received and tax paid as your employer will give you a P60 if you are employed at 5/4 or a P45 if you leave part way thorugh the tax year.

Thank you