I agree with the comments about having to have an "engineer" to swop the box
I recently had a problem with the box and a replacement was required
I also said "put one in the post" to be told "this is not company policy"
So unplugged box - packed everything - and waited.
Fair to say he was on time but then just left the new unit with me and took the old one
I fitted it
So a waste of engineers time and my time