Introduction to ArtSleuth Studio

We have writings found on the back of an old frame, all leads were dated early 1800s or b4. One inscription, 30-11-1807 proved th be JMW Turner's writing, 2 weeks after he was appointed to Royal Academy. There is a bequest in Turner’s writing, "Thompson from William." Thompson was Turner's son-in-law, who's wife n kids died in 2842, and in 1846, Turner takes his daughter off the will, disinhereting Thompson. Paul Biro photographed a 9-point grid under the 1st layer of paint drawn over the original sketch, a transfer method. The 9-point grid we found in Turner's teaching sketch book . Most inscriptions are in the wood of the frame, small, including a tiny signature,
JMW Turner. (Signed.) There is a number, "46" the year Turner took Georgianna off his will, and a large "G", probably for "Georgianna." Thompson printed his name on side of linen, dated after Turner’s demise. Linen thread count is perfect. Can you authenticate the handwriting?
Then the painting?