You can get duplicates from your dealer easily enough.
Our car only came with one 'proper' key and one wallet key. (54 plate)
We ordered another, but wanted the full key with the lock/unlock buttons. However, there was aq slight mix-up at the dealers and they only ordered us a flat one. i.e. it would start the car but you'd have to use it manually rather than remotely.
We then ordered the full key, so now we have three keys plus the wallet key.