CSCS Or ECS cards

I have just secured some appliance install work in newbuild properties,and one thing that has been brought to my attention is that I require a CSCS Card or an ECS card to even step on to a building site.

I dug a bit deeper and ECS have a category called Home Electrical Appliance Installer which is what I am applying for .

The reason for the post is just a heads up as I am informed that if you were to attend a property on a site to fix an appliance you still need a card if the property hasn’t been released to the homeowner
Cant remember how to post the link but just Google ECS Or CSCS for info