@bsc
If you want Shiraz from the Old World then the first thing you need to understand is that in France it is called Syrah, and that with a couple of exceptions is it rare to find it anywhere in Europe as a single varietal, even less to to find it labelled as such.
The Northern Rhône is the main exception. Although some appellations permit the addition of other varieties, by and large anything from there will be purely Syrah although it almost certainly won't say anything on the label. Look for appellations such as Côte-Rôtie, Hermitage, Crozes-Hermitage, and Cornas. St Joseph is another, but the wines tend to be thinner and lighter than elsewhere in the Northern Rhône.
In the Southern Rhône Syrah will often be present, but as a general rule will be a junior partner in a blend with Grenache and possibly some Mourvèdre. Same applies to Côtes du Rhône-Villages which are all in the centre or south, although you might find a generic Côtes du Rhône made in the north from pure Syrah.
The other exception is the Languedoc-Roussilion, where you are much more likely to find varietal wines under the Vin de Pays d'Oc designation than in the traditional appellations where they still blend everything.
There are a couple of enterprising producers in Portugal growing Syrah/Shiraz in the Alentejo region. Although most blend it with indigenous varieties there are a few varietals (Herdade do Esporão is the producer I'm particularly familiar with), but if anyone does still import them to the UK you'll have to hunt around for them.
Adding sugar to wine before fermentation has been practised for centuries in the Old World to boost the alcohol level in years when grapes don't properly ripen - it's called chaptalization. It also happens in Champagne - the dosage - to enable the second fermentation in the bottle.
Adding it (or, more likely, adding concentrated grape must) to sweeten the end result is mostly a German trick. The Italians achieve the same sweetening effect by drying a proportion of grapes to raisin levels. Port is made sweet by stopping the fermentation with brandy before all the sugar has turned to alcohol.
Obviously in the New World they don't bother with fussy old traditions, and if sweet-toothed Brits want a sweet wine they just shove some sugar in!