Our website is built on a platform that used counties and county codes as part of the address. The 3 letter county code appears in your account ahead of the postcode making the postcode look wrong. This is not the case and the county code does not appear on the shipping label.
For example, if you live in Berkshire the county code is 'BRK'. This would mean your postcode would appear something like BRK RG30 4JN. The postcode that appears on your delivery label would be RG30 4JN. The 'BRK' is only ever seen in your account and affects nothing.