S Accounts

Hello guys, I am having trouble understanding exactly the process of registering a non UK Resident for self assessment and would appreciate if someone could explain this fully as it sort of seems like everyone is saying something else and after hours on the phone with HMRC Im still not sure how to go about it. The situation is that a few clients which are directors of a limited company that is registered in the UK get income in the form of Dividends from that company however they don't live in the UK therefore don't have a NiN or UTR, We need to do a self assessment for them for the dividend income they receive however they cant register on the Gateway ID as they don't have a UK address and I got told they would have to call HMRC personally and get a temporary NiN first however they don't speak English well enough to be able to do this and secondly from what I have read here then there is no need for a temporary NiN as they can process the SA1 and issue a UTR without a NiN is that the case or must they have the temporary NiN first? The second issue is when filling the SA1 can the client use a correspondence address in the UK or does it have to be his actual home address abroad? we are worried that if it has to be his actual home address then we wouldn't meet the deadline as the whole process is likely to take longer than a month and it is already the 27/09 when Im writing this. So what would be the best and quickest way to get the client issued with a UTR nr and registered for Self assessment? And are we able to fill out the SA1, SA100 and SA109 print it and send it to HMRC by post or do we have to call and request them to send it? Also we do have software which we can use to file the self assessment online if the client has a UTR number however it doesnt say on there which is the form SA109 we have a different one called 'residence status' so would that be sufficient or would we have to send the paper ones by post? Any replies on what the best course of action to take are greatly appreciated.