Any question answered...

I bought a bottle of olive oil in a small organic shop yesterday, it was a fancy non filtered italian oil on discount, but when I got home I realised it was expired on 12/2013. So 7 months ago.
Yesterday was late to go back so I returned to the shop today. The girl at the counter told me that the bottles are in offer because they are expired (she didn't tell me that the day before tho) and so I couldn't get an exchange or refund. i left just because i didn't want any troubles.
I don't know how the rules are here in Uk but in Italy you can't sell expired stuff (according to the label).
For as much as I know they could have got for free these products (where they are not possible to sell after expiry day) and then made some money out of junk.
Is there an office that I can call? Health and safety?

If it's a use by demand your money back.

If it's a best before, it's probably caveat emptor, but I'd still demand my money on the basis of good customer service being to inform someone you're selling past-best goods.