The halfords do not keep spare keys for the roof boxes becuase each box comes into the store with the keys for the box attatched. If it is a Halfords own brand box normally the number is on the outside of the lock, not very security conscious but handy if you have lost the keys and don't have the key number. If this is the case you could be lucky and tyhey may have a box with the same number of key and you may beable to work something out with the store. If the box is a Thule box or another brand it nis highly unlikely that the store will be able to do any thing for you. It is not that the staff are being awkward but they for security reasons people can not normally just walk in and buy them because dishonest people could get hold of the lock numbers and steel the contents of boxes of cars left unattended. It is worth a try going into the store though, you never know your luck could be in.