Neither FAA nor JAR require these to be full stop.
For FAA purposes, night landings used for currency must be done to a full stop. See 14 CFR 61.57(b):
(b) Night takeoff and landing experience. (1) Except as provided in paragraph (e) of this section, no person may act as pilot in command of an aircraft carrying passengers during the period beginning 1 hour after sunset and ending 1 hour before sunrise, unless within the preceding 90 days that person has made at least three takeoffs and three landings to a full stop during the period beginning 1 hour after sunset and ending 1 hour before sunrise, and—
(i) That person acted as sole manipulator of the flight controls; and
(ii) The required takeoffs and landings were performed in an aircraft of the same category, class, and type (if a type rating is required).
As for logging instrument time, whether you're on an IFR flight plan is really irrelevant. Log the time spent operating by reference to instruments.