Hi Donna , sorry to be a pain , but we cannot trace "Our" Isabella's death/burial , she was on 1901 census aged 76 , you have already checked the one aged 90 in 1914 , and it was not her . The two other possibilities are not correct , but they are the only ones , have checked the Civil regs and ages are the same . Could you please check the following :

6 March 1902 Braddan aged 87

9 March 1902 Rushen aged 72

Thanks
David