Glass/Acrylic sheet approx 650mm square (Ashton-U-Lyne OL6)

I'm hoping for 2 clear pieces actual size is 650mm by 530mm. I can cut from a larger piece usually! I currently have 2mm acrylic which is too flimsy (it is for secondary glazing) so glass is preferable or 3 to 4mm acrylic. A larger double glazed unit even if misty would be OK. Thank you (it often takes me a while to reply)