If you are willing to travel this store has stock available now.
The 27 series multidisc is a multi-purpose plastic plate compatible with the Trangia 27 Series cooking set. Space and weight saving gadget, the multi-disc is designed for wild or campsite cooking and has multiple uses. DofE Recommended Kit which deatures on the DofE Expedition Kit List.
Great wee product that protects your frying pan, with slots in it for the 2 pots and a surface for chopping. It's worth buying, if you like trangias.