I'm pretty sure if you're a TV subscriber enjoying active TV Boosts then the TalkTalk support team will replace the broken remote for you.
What you'll need to do is please ensure your Community Profile Personal Information (Click here) includes your TalkTalk landline phone number and an alternate number (mobile recommended). Add, then scroll down and save changes. The TalkTalk Community support OCE will then be able to link to your TalkTalk service account.
The TalkTalk Accessories Store is also able to supply additional remote controls for under £12 including delivery.