Doesn't seem a bad deal with calls (if you use your landline) I've been with them on and off through the years, and they've usually offered TV for free. I get the impression TV is a loss leader for them. Each installation represents an opportunity to sell additional (more profitable) paid TV services, over and above the base package.
Been with talktalk for years my current deal is £20.95 a month for line rental unlimited calls 24/7 faster fibre with boost & tv
You need to check what speed your router is syncing at (by logging into the configuration page). The back of your router will have the login details you need to do this. Unless you have changed it, the default username will be: admin The page can be accessed at 192.168.1.1
Just used Google to check internet speed
So how did you establish you download speed?