Here's some info that may be of assistance. I presume you've purchased in the UK from a high street store.
Under Sale of Goods, retailers must provide goods of "satisfactory quality". Failure to do so entitles the purchaser to reject the goods. This is a basic statutory right that cannot be avoided by the retailer, even if their own terms and conditions state otherwise.
I don't know what the fault is with your TV, but chances are, you could have lawfully rejected it, especially if your TV was expensive and the fault significant. However, you gave the retailer the opportunity to repair it. This wasn't a mistake on your part and you can even work it to your advantage.
The question is, what do you want out of this situation? Do you want a brand new TV? Do you want recompense for the time taken to repair it? Are you afraid that the TV is "damaged goods" and may develop problems again?
My advice would be to give them time to repair the TV. The 24th isn't too far off. However, you could speak to the retailer in the mean time and negotiate an extension to you warranty (or even gift vouchers) as a form of recompense for the inconvenience caused to you. A good retailer will do this purely out of goodwill, regardless of legal obligation if you suggest it.
The worst case scenario is if time drags on and the TV isn't returned, or upon its return it develops another fault within a short space of time. In the first case, you could write a letter demanding return of the fully repaired TV by date X or you will be returning to the retailer for a full refund (i.e terminating the contract due to the retailer being in breach). In the latter, you could reject the TV for not being of satisfactory quality - and demanding a refund or replacement.
