Your CV should be no more than three A4 pages.
If in your CV/resumé you claim engineering work experience
of 12 months or more, then you must provide certified copies
of original employer reference letter(s), and certified
translations into English where necessary.
If a career episode is based upon engineering work, then you
must provide an employer reference letter.
Certified copies do *NOT* equal to notarized copies.
You do not need to provide notarized copies of your reference letter. Just send them the original reference letter with the signature of your manager should be fine. You do not need to notarize your working experience either.
If you could provide original reference letter, then you do "NOT" need to provide certified copies.
This is the same for you transcript and diploma. If you could provide the original envelop sealed transcript and diploma, then you do not need to provide certified copies.
I sent EA the original reference letter, transcript and diploma and they were fine with that.
You do not need to notarize your working experience either.