When updating share prices version 1.1.0 RC2 is calculating share values too high by a factor of 100. In v.0.9.9.0 it was calculating them correctly. Yahoo reports the value of the share price in pence, MMEX records the value of the share price in pounds (UKP). In MMEX, at the bottom of the share price page, it shows the calculation performed and shows the source of the error.
Fixed:
https://github.com/moneymanagerex/moneymanagerex/pull/109