A PS4 Pro that starts £349.99 and drops to £315.00 due to the code "CEBAYARGOS", receives a bonus of 5% TCB cash-back and £5.00 additional cash-back for transactions over £50.00. According to thevman2k3's post, Argos will present you with a £10.00 voucher for spending £100.00+ at their eBay site: http://www.hotukdeals.com/deals/brand-new-ps4-slim-500gb-call-duty-infinite-warfare-console-bundle-ebay-argos-2570524
If you'd like to be safer, use TCB for 10% cashback at the main Argos site and you'll be sure to receive the £10.00 voucher, although it is slightly less of a discount!
Hope this helps someone!
Update 10/12/16 9:45AM - Still available in Argos' Luton stores if anyone's interested. Not sure why this is marked as Expired.