Entry Requirements for Ireland

Hi, I am new to this forum, so please don't hesitate to tell me I'm in the wrong place etc.

I am British and my wife is South African (SA).
We will be touring the UK and Europe in our new Roller Team motorhome soon :-)

SA passport holders do not require a visa for Ireland, but looking at the SA consulate website is see "All travelers" [not just SA] must be able to supply "Return airline ticket and Proof of accommodation." 

My question is - will a return ferry do as a "Return airline ticket" and is a Motorhome considered  'accommodation'?

I have obviously asked the question with the SA consulate, but I'm not holding my breath while I wait for a reply! I am hoping someone here has had experience of entering Ireland with a foreign spouse.