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?" :)
In English we just don't say "Have you gone?"
IT'S A PHYSICAL IMPOSSIBILITY!
If somebody "has gone" they are not here now. If I ask, "Have you gone?" and the answer is positive then who am I talking to?