Hello Richard Landy,
In Azure API Management service, if you are using the Standard tier, there is no enable option available. This is by design, as this tier does not include the enable option, as shown in the image below.
In this tire we can only see below option.
So if you need the enable option, we suggest you upgrade to the Standard V2 so that you can use the enable option as shown in image below.
I think the above provided information will helps in better understanding and solve your concern, if you have any further concerns feel free to reach out to us.