Item sent to wrong address - no refund or replacement

Buzzzcut

Thanks for all the replies, I didn't expect such a detailed response.  
So after a few days the company contacted me and said that as there was no flat number provided on the incorrect address Royal Mail couldn't deliver the package and so returned it to the company, they've since refunded me the full amount. It's lucky for me that it was a block of flats as otherwise the package would still be at the other address.
This is certainly quite a strange turn of events as I initially received a Royal Mail "delivered" email complete with a photo on a random doorstep (I could see the incorrect postcode on the photo), the company was using this evidence as a reason for no further action.
BTW - The site operates a "start typing your address" logic rather than an "enter your full address", if I start typing my address it defaults to the alternative, I would then delete the full postcode and add mine.  I think I must have deleted all but the first letter of the postcode and absently minded didn't notice when I filled in the rest. 
To those asking, the impossible W22 4RT postcode exists on the online order so they allowed it to be processed, another comment is that it doesn't match my billing address, but I've no idea if those are matched during payment.

TLDR - The package couldn't be delivered, it was returned to sender and I received a full refund.