Not specifically, but as a general comment. I went to a big Argentine tasting a few years ago (I reported it on TMF, ah here we are - really 7 years ago?
http://boards.fool.co.uk/c244t-a-lot-of ... 86242.aspx) and it was striking how consistently good the £8-11 reservas were but how they struggled to control the balance on the premium ones. Exchange rates and demand will probably have pushed those prices up towards the kind of thing you were thinking of, and I suspect they've learnt to control the premium ones a bit better now, but it's something to bear in mind.
Argento has always struck me as a Doom Bar equivalent - competent enough but a bit dull. To be honest, I suspect you'll struggle to get any kind of decent premium malbec in a supermarket (except perhaps M&S/Waitrose). I would have said your best bet would be getting to the wine shop at the Gaucho off Piccaddilly, but I haven't been there for a while and looking at their website it looks like they may be online only now?? Might be worth popping by if you're in the area.
Otherwise, on the basis that when someone says they like "malbec", they're really saying they like sweetish, rich wines without too much tannin, you might be better off with supermarket amarone which comes in around that price. Or go to Cahors which is the original home of malbec where it's known as Côt - again a good one might be a bit too specialist, although I'd probably trust the Waitrose one at £9 - but it probably won't taste like the Argentine malbec that they are thinking of.... Depends whether they're interested in learning more about the grape or just want something nice to drink.
