Did they tell you that as part of trying to sell you their installation service?Currys - which I often do not believe
Go back to them and ask them what sort of certificate they provide.
You're right.I thought the certificate was for the main installation or adding any extra components, like installing the wiring and fuse for a shower , that type of work
It doesn't.But as a Cooker is hardwired I wasnot sure if it also fell into this certificate requirement now