Neil, I am also searching for Dingles in Cornwall. My family lines are primarily from Pelynt, Talland, Northill, Duloe. I have the following on the Dingle line:
William Dingle b. abt. 1812 St. Pinnock (?) m. Rachel Jago b. 1812 Pelynt; children (all born in Pelynt)Rachel Jago Dingle, Ann Dingle, Mary Susan Dingle, John Jago Dingle, William Dingle, and Letitia Dingle.
Letitia m. James Curtis and lived in Polperro.
John Jago Dingle m. Mary..... in Pelynt, and had children: Elizabeth Rachel b. 1870 and 10 others (I have their info).
Elizabeth Rachel m. Richard Charles Jane b. 1867 in Liskeard. This couple emigrated to canada in 1906.
These last are my g-grandparents.

Please contact me if you think any of our info may be worth while exchanging.