Large Square Porcelain Floor Tile eg 600mm x 600mm (Bensham NE8)

I'm looking for a single large porcelain floor tile, min size 595mm x 595mm, to complete a project.
Would prefer a dark tile, eg grey, black, anthracite, or anything that's not too pale.
Seems a shame to buy a box of 4 when I only need 1!