Hi Rachel, I’ve found the stencil you’re looking for, spotted it in google images, I went to the page it’s linked to, Kelly Jaynes but it doesn’t look like they do it anymore, I’ve included the link for the page where I found it, maybe you could contact them and find out if they still do it or if they know of anywhere that stocks it.
Good Luck xx
https://www.google.co.uk/search?q=square+damask+stencil&client=safari&hl=en-gb&prmd=sivn&tbm=isch&tbo=u&source=univ&fir=8FHS5N9Q2komrM%253A%252COzQ0dALKWJZUHM%252C_%253Bmvzl7WSPNhYsiM%253A%252C5RciEr_nlE3trM%252C_%253BJxqIYrCJisuUOM%253A%252CFeYxMZ1trFYU7M%252C_%253Bi5_xbRljK8hJWM%253A%252ChuQ4hhIP00B-LM%252C_%253BZf4fGjGkct04nM%253A%252CTSKAClu3I8K0XM%252C_%253BrszF32tWzGvNLM%253A%252CUsjw0O8uQKYMkM%252C_%253B9ju5A1KKQIxcPM%253A%252C3WI8GLwwN2FrKM%252C_%253BHdeBbtuNcmM0VM%253A%252C—EDlo-RTjk43M%252C_%253Bj8S6zD50M5I57M%253A%252CnhSgGZayyS5gkM%252C_%253BeqMlRqOXnDVhRM%253A%252C5RciEr_nlE3trM%252C_&usg=__kP1KdwvjGmpnFfeOlx-YsJm1dI%3D&sa=X&ved=0ahUKEwjp5Ymq16nTAhXHcRQKHfn9AF8Q7AkIIw&biw=375&bih=628#imgrc=FcJdMjWQg773M:
Blimey that link was bigger than I thought it would be
