So we raced back to the shop we bought from to cancel the order, trains not withstanding (but that's another tale!). Understandable they did their best with plenty "umm-ing" and "err-ing" and "we can match that" and "let me ring for authorisation" but in the end they couldn't match or beat it nor could they break our resolve to get our money back!
While on the subject of money saving and Argos, may I recommend, for UK persons, the National Shopping Monitor. You scan your shopping every time you buy something, return your receipts and they give you points. Every 10,000 points equates to £10 in high street vouchers or give the money to charity - various redeemables, its up to you what you do with it. The points build up fast (example: every week you scan you get 1000 points). You get points for receipts, bonus points each year, points for scanning and then they have other things like surveys which will give you points should you choose to fill them in. I have never been bothered with spam from them nor from other companies as a result of them and have been with them for several years now. I have had so much 'free' stuff with my vouchers, they are great for little gifts to yourself, extravagances you don't usually allow (like rowing machines!). I have given the best link I can, a search maybe better, oh and so you know this isn't some paid advert thing, I just think its pretty cool!