The John Lewis group are decent retailers. From my 15 years of buying almost everything from them, they have never done anything wrong. I have only ever had to use their aftercare servcie once when the screen went wrong on my microwave a good while ago. Was replaced and no problems since. I have had bad experiences with aftersales in currys and comet a few years back which prompted me to switch to JL. Their prices are not always the cheapest but will price match if you can meet their criteria for a price promise. If you want the very latest computer equipment though, I think ebuyer and the like would have it avilable first and cheaper though.

Trading Standards would be all over them like a rash, so if you have suspicion any retailer is selling goods as new, when they are B/C grade products then contract Trading Standards.