I’ve found this free online tool, which is useful. You can calculate the return on investment of a stock with dividend reinvestment included. This is useful because in the Freetrade app (and also with other brokers) you only see the ± in share price of the stock.
To me at least, this makes dividend paying stocks look less favourable at a cursory glance, because their ROI is not shown, only the change in stock price over time.
This specific tool is only up to date to March 2018, so if anyone has a similar tool that is still up to date, that would be useful. Maybe this could be a future feature in the app, along with auto dividend reinvestment.