One step forwards/sideways/backwards : Went in to pick up my 180cm white & silver... half expecting the Silver to be the wrong size... but both 180cm HOWEVER my silver one had been damaged in transit with the end of the clear plastic box totally knocked off and tube torn off a bit and end of the fitting/slats not 100% so had to reject that and order a fresh one to be delivered instead (and they waived the £5 delivery charge of course). The white one is branded Harrison Drape. The blinds appear in their printed catalogue at this £15.71 price (where we had to find the part # to reorder the one to be delivered). Thanks to OP anyway
PS: Two days later and had all my refunds/credits applied and the replacement Silver delivered "between 7am and 7pm" (actual 10am). No extra packing beyond that clear plastic box, but this one arrived in one piece, a little bit knocked/cracked but blind looks perfect so alls well that ends well - eventually. Good find OP!