Hello Rupert111,
I understand what you mean about the engineer just for a plug socket but certain equipment such as this type of plug, we're unable to order them from here unfortunately. Are you trying to perform a self install and you see a missing plug? I ask because if so, an engineer may be required to make sure you're installed properly and they'll be able to check everything else.
I've just had a look at your account and can see that an engineer has been arranged since you posted who will have the necessary parts required if it an install.
Thanks,
Lisa