> Would this phrase be translated as "Sir, may honour/good fortune be
> granted to you by comming here?"

Dear John,

No, I don't think so. "bhaddaka.m" is a visesana of kamma.m, which is
assumed:

> bhante, bhaddaka.m vo kata.m (kamma.m) idhaagacchantehi (tumhehi)

"bhante"=venerable sir, "tumhehi"=by you "aagacchantehi"=one who comes
"bhaddaka.m"=a heightened (lit: developed?) "kamma.m"=action
"kata.m"=has been done.

Best wishes,

Yuttadhammo (Phra Noah)

ps: I would suggest either "Yuttadhammo" or "Phra Noah" as an address.