So I wonder if I just stick down, under 5. Ratings Held, Night qualification and leave the rest blank
If you want it make sure you do
put it in under Section 5 (Date of Test = N/A)
CAA staff are likely to look only at what they are asked to. They are
very unlikely to study your old License to see whether it says "Limited
to use by Day only" or not - unless you have nudged them in that direction.
Yes, everything should be on your computerised record with them, but.....
And don't forget to send in a record of your Language Proficiency
(CAA not having a record of it has been one of the biggest reasons why
EASA License applications have been rejected/delayed)