Hi Shirazzy,
I started a strawberry Ribena off 3 weeks ago using 1L bottle of the concentrate by itself without the grape juice it's bubbling away quite nicely. I suppose it depends on preference and how much your making. there's a how to guide for both strawberry and normal Ribena on here with advice and different recipes.
I managed to talk my mum into buying a bottle during the weekly shop (the joys of being a doley living at home ) So that'll get brewed as soon as I get chance, the recipe I'm using is ribena + sugar to 12%ish + water. Hopefully it turns out well (my last attempt was a bit interesting, but then it was rushed and done with a lot less experience, so saying my old roommate enjoyed it).
I am using it in a WOW as replacement for orange juice,
and also as a replacement for one litre of rgj in a
Richards red, now expected to ferment out at 12.5%.
Pete