But, don't purely go by other people's past experience, the policies on prohibited & restricted goods changes occasionally for different carriers and methods. It's more to do with how they carry it in transit and the impact of the dangerous goods act
If there is any possibility of it going by air, even if still in the UK then it cannot be sent by that method
Pick a courier, look up their prohibited lists. If there is any mention of pressurized cylinders then don't use that method.