Interest free or credit card purchase

Loanorcredit

What is better for me for a £1600 purchase?

Apply for a new credit card with the post office or the company is offering 12 month interest free credit? I can afford the repayments over both durations.

Which is best option? Is there any benefit one over the other or does one effect my credit rating more than other?

Any help welcome.

Thanks

DCFC79

Shouldn't have posted the question twice though.