Double swiping of payment cards, legal?

I went into a home furnishing store today to purchase some stuff and attempted to pay by maestro debit card. They have a standard UB terminal that accepts maestro. This was clearly marked on the machine and on stickers around the till and door area.

I was not allowed to pay with maestro as their till would not recognise my card. They swipe thru the till and then use chip and pin via the UB terminal. The till and CC machine are not connected at all. The shop assistant was quite rude about it.

Is this legal/ethical? I thought the whole idea of chip and pin was that you never have this sort of activity.

Why do you seem to think that it might not be legal or ethical? I doubt that legislation deals with this sort of thing at all. I don't really understand where ethics come into it.

Data protection does imho. Why do they need to store your payment details in their own till?

How do you know that they are storing them? Did you ask?

I did ask.

And did they say they were storing the details?
Regardless you are covered against fraudulant use anyway

Homebase to this as well, basic I think it is becuase they have a crap POS system which does not link to credit card terminals.