Why are M&S charging £10 for 50ml of REN body lotion in the sale?

[LadyLapsang]

Online and in store £10 for 50ml of the neroli and grapefruit body lotion, which M&S states is a reduction of 50%. I suggested to the assistant that it was an obvious mistake, but she just consulted her cash register and told me it was the correct price. Full price from REN is £20.00 for 200ml.

Full price from M&S looks to be £20 too. Might be worth getting in touch with them though, as a search on their website brings up the 50ml version marked as sale, but priced at £10 from an original price of £6. Looks like a pricing glitch!

Well I told the assistant in store but "the computer said no" and when I pointed out it was obviously wrong she just ignored me and packed my other goods. The website still has it "reduced" from £6 to £10.