How is a CNAT different from a GCSE?

On my results sheet in 2014, my school printed:

Board
OCR

Year
2014

Opt
J800

Option
ICT

Qualification
CNAT

Result:
M2.

I'm applying for University this year and I realised I've lost my certificates, I'm apply for new ones but under qualification type I put CNAT since that's what it says on my Results Sheet.

CNAT is short for Cambridge Nationals.

Nowhere on the OCR website to the state anything regarding CNATs except on the ICT J800 page.

Why is it such an obscure qualification?

When I applied for it they told me I was doing a GCSE, I pushed further with this, asking staff and students and was assured I was doing a GCSE. I accepted that this was all a lie when I read M2 (Merit Level 2) but it was too late by then and I no longer care.

Is a CNAT separate from a GCSE?
What is it's currency?
Should I put GCSE under qualification type on this form?
Should I put GCSE on my CV too?

This is a concern because OCR says:

"We are unable to supply replacement certificates to candidates for 14-19 qualifications after six months of issue. If you lose your certificate you must apply for a certifying statement of results.14-19 qualifications include:

•

AEA

•

Asset Languages

•

Cambridge Nationals

•

CEE

•

CSE

•

Entry Level Certificate

•

FSMQ

•

GCE A/AS Level

•

GCE O Level

•

GCSE

•

GNVQ (post 2001)

•

STEP

•

VCE"

As you can see CNAT is not on this list.
Did my school mess up? Should the results sheet have said GCSE or something else? It wouldn't be surprising if they did.