Quick answer
Yes — any socket circuit that could be used to supply equipment outdoors must have 30mA RCD protection. This includes garage sockets.
If you have electrical sockets in your garage — especially if you use them to power tools or charge an EV — they must have 30mA RCD protection. This is a Building Regulations requirement. Any socket that could be used to supply portable equipment outdoors (including garage and outbuilding sockets) must be RCD protected. If your garage was wired before modern regulations, it may not have this protection. If you are adding a new socket in your garage, a qualified electrician must install it with RCD protection.
Need more detail? Choose a view: