maximus610,
If you hold a valid IR then you do not need to have carried out one night landing in the previous 90 days (the fact that you are not qualified to teach for the IR is irrelevant).
FCL.905.FI FI — Privileges and conditions
The privileges of an FI are to conduct flight instruction for the issue, revalidation or renewal of:
(e) the night rating, provided that the FI:
(1) is qualified to fly at night in the appropriate aircraft category;
(2) has demonstrated the ability to instruct at night to an FI qualified in accordance with (i) below; and
(3) complies with the night experience requirement of FCL.060(b)(2);
This only applies if you're carrying passengers at night. A night rating student is not a passenger. The instructor can effectively do his "one at night" whilst instructing the student, who logs Pu/t
I am sorry Mr A but this is incorrect - otherwise there would have been no reason for EASA to include the paragraph FCL.905.FI(e)(3) at all.
To instruct
for the Night Rating an FI
must comply with the night experience requirement of FCL.060(b)(2);
The only case where, provided it is agreed that a student is a crew member not a passenger, this experience requirement would not apply is for instruction given to someone who already holds a Night Rating (Revalidation and Renewal not being applicable) - Such as someone requiring one night landing before themselves taking passengers and preferring to do that with an Instructor instead of solo,