They 0.5 OD 0.3 ID is on back order, however I just contacted the chain of stores and they very kindly redirected me to a webstore where I could purchase the products from. It's sad as the crew at the shop were really great guys that although had no clue about WWI aircraft (They only sold SWS ZOUKEI-MURA kits) they always took a huge interest in the work I was doing.
but if this place can ship to Japan for free - I will certainly be using them in future!