I dunno, I'm just going to cook it an eat it plain I think. Maybe a little garlic and in the pan when it's roasting, then deglaze with water/wine, reduce, beurre monte as a little pan sauce whilst it rests to moisten the plate a touch but other wise I'll just eat it plain.
I tend to do either that or if I can be fucked (which is rarely) I'll make bernaise which is my favourite steak/roast turbot sauce I think. When I spend the money on something like an expensive steak like that or a pricy bit of fish I think to just sit and eat that thing with bernaise and just have a greedy sized portion is the way to do it for me. No need for any accompaniments really, just enjoy the thing for what it is with a little dipping sauce or jus.