Translation:Have you gone to the office?
here, I think we would say have you 'been' to the office instead of 'have you gone to the office'
If you want to say "Have you been to the office?," you would say "Dych chi wedi bod i'r swyddfa?" :)
There is a slight difference in the meaning in English between simple past and present perfect too, although they are often used interchangeably in speech.