Our friends at eWRC have just made an assumption I think. The names are taken from this press release - http://www.walesrallygb.com/news/3688.php#.V_JGWfkrLIU
But if you read it closely they've kept it deliberately vague as to what he's driving. We know there are 64 entries but the list hasn't been released which is frustrating. I don't know this for sure, but watching how the MSA/BRC PR team has utilised Motorsport News this year there could well be some form of announcement on Wednesday.
Would be a bit of a waste to enter Elfyn in an R5. Plus from what I understand he'd have to run well down the order as he can't now be classified in WRC2. I think he'll be in a WRC.