"Can someone explain the difference between council and law officer? I mean I know council are their lawyers but not the law officer bit"
IANAL and I'm not too sure about the law officer role - counsel is basically the QC who will likely be the one to be arguing the merits of the case they're instructed on. In any cases I've dealt with, the counsel opinion is the best overall summary of your key arguments & their legal merits, usually includes any case law that's relevant or helpful & supports or undermines parts of your arguments. Usually, the client should pay v close attention to what counsel says.
Clients can go against the advice, but it's a huge risk to ignore what counsel says about the strengths or weaknesses of your case. I've been involved in civil stuff where we all have a range of opinions & views on the case, the strengths/weaknesses & whether to take the risk of costs on pushing onto a full court hearing etc. But it's extremely foolish to believe that the QC employed to argue your case isn't the best authority to assess the merits. Mind you, I've never been in the position of having law officers or the Lord Advocate to opine on counsel's opinion so maybe Scotgov had better reasons to ignore the assessment of the prospects of success that I've ever had!