Before investing in the Bonds, this Pricing Notification should be read in conjunction with the Preliminary Prospectus. Terms defined in the Preliminary Prospectus shall, unless indicated to the contrary, have the same meanings where used in this Pricing Notification. The particulars to be specified in relation to the Bonds are as follows:

Issuer:
Principal Amount:
Coupon:
Day Count Convention:
Issue Date:
...
Form:

И вот: Interest Payment Dates: Semi-annually in arrear on 23 June and 23 December in each year, commencing on 23 December 2017.

...В единственном числе никогда не видел... За прошедший период?

Спасибо.

23 июня платеж за предыдущие шесть месяцев (т.е. за период с 23 декабря прошлого года и по 22 июня года текущего) и вайса-верса.

In arrear | Practical Law
https://uk.practicallaw.thomsonreuters.com/0-503-9016

A term used to describe the payment of contractual sums that have accrued over a specified period and which fall due to be paid at the end of such period.