I've just bought a stick from Argos that says it comes with a 3 month entertainment pass. Presumably this is valid for a year or however long the other passes are ? The reason being I still have 2x2 month passes I want to use first. Is there a link that explains this some where I did have a look. Presumably it can go back to Argos if it doesn't work when I get around to redeeming it.
With the voucher pass that comes bundled with the stick or boxes, you have 12 months to redeem and start the pass or passes in the box from date of purchase.
You can apply a new voucher code or redeem a new voucher pass on your account within the last 30 days of your offer expiring on your account.
If you have 2 x 2 month vouchers spare and haven't used them yet, then you should be OK as long has you redeem the recent 3 month pass with the stick from Argos in the next 12 months.
Always keep your receipt as proof of purchase, just in case you encounter any issues when redeeming the 3 month voucher, where the receipt would also act has the guarantee for the stick.