The tissue you that I was strengthening with matt medium, became stuck on the plastic - so that was not a good idea.
Stitched the other piece to the background and then painted it with acrylic wax, then painted the Plums and Leaves with diluted Golden acrylic.
Then stitched around design with cotton thread. Removed white tissue easily (this was the tissue bought for gift wrapping. Tried to stitch around the design again but this started to cut both the top and bottom layers of tissue.
Quite happy with it, if I decide to make this piece I will need to dye more fabric and paint tissue with same coloured dyes.