Hi Gareth Redex is not cheap or the cheapest, all branded product comes from the same plants just different labelling and if you as I have had to search about for better deals you would soon find out that the average price is over £20 for ten litres, therefore one would conclude there is no such anomaly as cheap adblue, as for the companies proliferating product range, over fifty years of trading and a multitude of products might just indicate they make a decent product otherwise they would have gone bust a long time ago, oldest saying in the world, don't knock it unless you have tried it, I have used both their adblue and a lot more of their in tank DPF cleaner over the years both with good results, after just shy of a million miles I think I should be able to spot the lemon by now.
Steve.