I have never seen one of these stands before. It is marked with "Wedgwood" and the mustache type mark as shown in the photos.
The teapot itself is larger than other examples I have seen of this form. The teapot is also marked with only "Wedgwood" and the mustache mark as shown. The lid fits both the teapot and the filter. There don't appear to be any markings on the lid, the filter, or the strainers/inserts.
I do believe that at least the 2 strainers with handles on them are Wedgwood pieces original to this set because the color of the clay and glaze matches the other pieces exactly, and one of them fits exactly on the small ledge near the bottom of the filter. The total height of the assembled pieces is about 13 inches. The teapot itself measures approximately 11.25 inches across including handle and spout, and just under 6 inches high with the cover.The diameter of the warming stand is just under 6.5 inches, and its height is approximately 4.25 inches. As seen in the photos, the teapot has old staple repairs to the handle and the tip of the spout, and a flea bite to the rim.
The warming stand, filter, and strainers are in excellent condition with no chips, cracks, flea bites, or repairs. The cover has a small chip and flea bite. There are some separations and spotting to the relief.
I have not tried to clean it. 1800-1820 Wedgwood Jasperware Large Teapot with Warming Stand & Filter Antique" is in sale since Tuesday, August 10, 2021.
This item is in the category "Pottery & Glass\Pottery & China\China & Dinnerware\Wedgwood". The seller is "jonesing-for-it" and is located in West Chester, Pennsylvania. This item can be shipped worldwide.