Hey Tytus, I use Sharescope for all of my data. unfortunately i'm not aware of an API to their data, so its a manual job for me to download, and then i upload into amibroker or quantshare for my backtesting
alternatively and more relavent, both ami and quantshare have APIs to yahoo so if its just UK stocks, you'd be fine. my data requirements yahoo cant provide alas.
then there's trading view..they have a scripting language to do simple backtesting.
hope that helps