I got my database back, with no loss.

Yes, sister Sarah Gelling (of JG & Isabella Cavendish family) married a John Shimmin in 1833 and there's a daughter Mary Ann Shimmin who married a Daniel Ellis in Liverpool and later they emigrated to Australia. See this BB Nov 5/07 by Maree Coates.

Further to the possibility that your Isabella Gelling als Cavendish lived long enough to make the census's, in 1841 there is a "Widow Gelling" 65 Y [born IOM, which doesn't agree with "England" in 1851] at the same address as in 1851 (Shaws Bro), with Eliz'th Gelling 16 Y. I looked quickly at the IGI and there are 3-4 possible Elizabeth Gellings b ca 1825. The House of Industry Isabella Gelling age 80 must be somebody else. I didn't find anything 100% certain to link to your Isabella, but it's worth putting it into the "possibility" pile.