I'm afraid I can't be of much help, being a Yank
I sincerely doubt they would have a problem as far as ethnicity though. Normally I start formal addresses (emails, letters, though not chat messages, etc.) with
[Christ is Born! --or whatever might be appropriate, if anything]
I'm so and so. I'm from such and such a place. I'm a part of such and such a group/parish [or this is my ecclesiastical situation]. Why I'm writing... yada yada yada. Thank you.
The only significant difference if I am writing to a bishop is that I say something like "Master, Bless" instead of "Father, Bless". Some of the links in this thread
might be of some help if you really want to get the proper names, addresses, etc. down.