Could a admin moderator please review my post.
It's not a deal. Vouchercloud's description is misleading, probably done deliberately so they can Earn commission. Anyone buying Advance tickets via this "deal" is paying more than they should, so it should be expired.
Apart from your last paragraph, all other points were covered in my post, including cashback deals. Also, I mentioned that it was originally spotted on VoucherCloud, and I thought it topical since folk may wish rail tickets for December, like leaving uni, and as I didn't need train tickets currently, there were no suggestions, as I didn't buy any. I didn't know if the 40% was discounted at final stages of checkout, and folk more accustomed to buying rail tickets for themselves may spot the value, and if the 40% off was a deal, as you ask.
I'm not sure what this "deal" is supposed to be. It says 40% off advance fares, but I can't see any evidence of these cheap fares, and I think it's unlikely there are any, because Trainline have access to exactly the same fares as all the other ticket sellers. What it probably means is you can save 40% by buying in advance instead of on the day. But that's the same for every other ticket seller. So its not a Trainline offer. Often buying in advance is no cheaper than buying at the station on the day. Sometimes you can save 75% or more. Trainline's fees make them one of the most expensive places to buy train tickets from. So you shouldn't buy from them unless there's a cashback offer that will more than cover the fees. If you plan to buy Advance tickets, try the train company's website first, as they sometimes have offers that aren't available elsewhere. Also check for offers on Nectar, as they often have things like 1,000 bonus points for various train companies. If there's a chance you might want to amend your ticket, buy from Cross Country or Transpennine Express, as they don't charge the £10 fee that is Standard on most sites.
Does seem unfair. I always use Trainline and agree with your tips so heat from me! Maybe it was the timing of your post. Lots of disgruntled commuters on stuffy trains and expensive season tickets perhaps?