The Tanner/OBriens want to get their stories straight with LE before they are further shoved by the McCanns. IMO And the story said lawyers, rather than lawyer. If they each have a lawyer, the plot thickens. If this story is true, that is!
At this stage, I think it would be unethical for one lawyer to represent two of the Tapas 9. There is just too much potential for conflicts of interest to arise, particularly if one starts implicating the other.
I would assume the UK would have ethical rules similar to those we have in the US restricting a lawyer's ability to represent two people who might have or develop competing interests as an investigation or trial proceeds.