Not a brilliant solution, but -
Install a download manager on your phone. ("Downloads" is a good one).
In safari, Go to your friendly torrent site and select the torrent's magnet link, copy the magnet link.
Go to
http://btcloud.io, login, and paste the magnet link there. btcloud.io does the torrenting, and once it's done, the file is available to download from there.
go to
http://btcloud.io using your download manager and download the file to your device.