I am having a problem completing the application form for a work visa.

Background:
I am a uk citizen based in the uk

I went to moscow on a business visa multi entry which i obtained in london

Whilst in moscow i was offered some work. So I worked there for 3 weeks.

Then the place that I was working at said I should get a work visa.

So they got the official invitation for me. And sent me for HIV test. They also gave me a contract.

I then came back to england last week and am going to the vfs global visa application centre tomorrow.

BUT one of the questions on the work visa application is: 'place of work or study'.

What should I do????

Can I put down the place in moscow?? Because if i do then presumably the embassy may be unhappy that i have worked for 3 weeks without a work vis??

Any suggestions gratefully received

Many thanks