Will shop change TV without a receipt?

[kid]

I want to exchange a TV dvd combi because the dvd part keeps pausing and is quite noisy when playing.
I don't have the receipt but have the box which has the stock code on it (proving that it was bought from that store in the first place)
I don't want any money back, I just want one that works properly. Do you think the shop will do that or should I phone customer services first?
We got the TV about 4 weeks ago.

They should replace or refund a faulty item. If you have proof of purchase such as the barcode or an entry on a bank/cc statement it should be straightforward to do in-store.

I did take it back to change it. I told them it was a present but they said I still needed a receipt. She checked with her supervisor and he said its fine as I just want an exchange.
Problem now is, I plugged the freeview box I bought into it, but that doesn't work. It just keeps saying 'no signal' so looks like I'll be back there again next week.
I'm convinced they will think I am up to something!