"...where this guys bureau apparently is quite often, but hestitate to bother..."
Well, your English is still better than my Polish, but wtf does a bureau have to do with this sentence?
"I'm passing, on bike, in front of a house, where this guy's bureau apparently is, quite often, but (I) hestitate to bother (him), especially (since) I have nothing to contribute, except good wishes."
Better?