The key remote contains a battery which will need to be replaced at some point. When the battery is on the way out, you will notice that the range of the key remote decreases or the indicators flash 9 times quickly when you lock / unlock the car.

You will need a single CR2016 replacement battery.

To access the battery, remove any keyrings from the key.

Separate the key fob shell using a flat tool. We found the metal tab on the smart keyrings to be perfect:

As the keyfob comes apart, the battery will remain clipped in to one side of the casing. The battery makes contact with the circuit board via the grey prongs and the gold pad. It is worth inspecting and cleaning these whilst the key is apart.

Replace old battery with a new one and reassemble.