Hiddy-- very glad to hear you are enjoying Argentine Wines. Thanks for your observation on my San Juan comment, in going back to read my post above it does indeed seem like Im somehow giving this region a "second-class" status. I will look into rewording my above post, since this is not doing San Juan justice.
I do stand by my comment that Salta is today clearly the superior Terroir... but this is a case of Salta being better, and not that San Juan is bad, or second rate. Its true that Syrah/Shiraz is the best offering from this province, although Im a huge fan of what old-vine Bonarda is producing. Also, as many of the wine aficionados on these boards know, Im a HUGE fan of the Mora Negra. Made by Finca Las Moras, Mora Negra is a blend of Malbec & Bonarda, and its a staple in the yearly purchases for my personal cellar.
Overall, Salta has more depth, tradition, and variety in quality wines than does San Juan. Still, as you very correctly point out, San Juan does have a few gems that are well worth checking out. One winery for you to look out for is Xumek. They make a Shyrah thats very good... Im not sure what the exact branding is for the UK but its either Xumek Shiraz or perhaps Xumek Sol Huarpe Shiraz. Hope this helps.