From Royal Mail's Post and Go News webpage today:
The Poppy design from the Symbolic Flowers Post & Go set will be
re-introduced nationwide from 19 October 2015. The stamps will be available from
Post & Go /Self-Service Kiosk post offices, BPMA, Royal Navy Museum and Royal Mail Enquiry office
It will also be one of the options at the Sindelfingen and Paris stamp exhibitions - see here.
UPDATE: The Poppy stamp has been reprinted with MA15 year code: there are reports of blank examples already being offered on auction site eBay.
ROC ~ Taiwan ATM Machine Codes and Locations - 076 Taipei Main Railway Station post office, 077 Taipei Shihlin post office, 078 Taipei Sanchong post office, 079 Taipei Danshui post office, 080 Taipei Xi...