Originally Posted by corporate-wage-slave

So where we are now is that we have
A) the NHS App right now (and some GP Apps),
B) the possitbility of reconfiguring that App quickly for travel purposes,
C) GP letters
D) The vaccination card already handed out.

1) Must be submitted in Icelandic, Danish, Norwegian, Swedish, English, or French. A certificate in another language may be valid if submitted along with a translation in one of the approved languages and verified by a certified translator.
No problem for A - D.

2) First name and last name (comparable to travel documentation).
No problem for A - D.

3) Date of birth.
A, B C.

4) Nationality
Why is that relevant? Anyway B and perhaps C, if GPs are spoon fed a suggested text such as "Patient A, holding UK passport 123456". GPs tend to be a bit hesitant in this space.

5) Passport number.
B and C Overlaps with 4 in practical terms and you could make the argument that a passport plus A meets points 4 and 5.

6) Name of the vaccinated disease (COVID-19).
No problem A to D.

7) When the vaccinations took place (dates)
No problem A to D.

8) Vaccination must be completed; see below for the number of doses required to complete the vaccination for each vaccine.Information on the issuer of the certificate (Healthcare Professional/Institution), along with a signature in the case of an international vaccination certificate.
No problem A to D, however the signature would be electronic for A and B, D has no signature.

9) Name of the vaccine.
No problem A to D.

10) Manufacturer of vaccine and
No problem A to D.

11) batch number.
It is on D, and recorded in the care records, but doesn't currently show in A. But presumably this could be addressed via B, and could be addressed via C.

So in summary, and leaving out signatures, a Brit going to Iceland with the NHS App, a passport and the vaccination card would have the information now, but scattered over 3 documents. The passport has to be deployed for UK travellers (which isn't obviously needed for Schengen and Nordic travellers). The question is whether Iceland would be OK with the scattered approach. I suspect they will eventually. If not then B has a bit of work to do, and C is the messy fallback.