Hi, I am looking to book a train from Southport to London next Saturday morning. I am looking at the 9.24 from Southport via Wigan into London at 12.12.
The off peak fare is £80.90 single, the advance single is £136.79.
I presume you're looking on Trainline, who add a booking fee. There isn't actually a fare for £136.79, but rather one for £134 and then Trainline are charging you £2.79 for the privilege of buying a ticket that most other websites would sell you without a fee.
The forum's ticket site also identifies cheaper alternative journeys, such as similarly taking the 09:24 from Southport to Wigan but then changing onto a slightly slower Avanti train that runs to Euston via Birmingham - this costs £61.00 for an Advance.
Why is the advance single showing as an option.
Because ticket buying websites generally offer you all of the fares that they're allowed to sell for a given fare. People may have reasons for wanting to buy a more expensive ticket, for example because of corporate/organisational travel policies that require Advance tickets to be bought.
Am I missing something about the £80.90 fare?
Not really. It's valid on all operators along all plausible routes as it's routed "Any Permitted" and it's valid all day as you're travelling on a Saturday.
That said, the Off-Peak Single costs 70% of the Off-Peak Return, so if you're returning at any point within a month it's probably better value buying that instead.
Also, my journey times seem to match with the super off peak times on the Avanti website but I cant see a super off peak ticket option when booking?
I don't know where you're seeing a mention of Super Off-Peak times? Avanti haven't ever offered Super Off-Peak fares for this journey. Avanti's website clearly states that they only offer Super Off-Peak fares between Euston and Milton Keynes.
In terms of long distance journeys, they only ever had Super Off-Peak fares on the London-Birmingham corridor; these were introduced by Virgin Trains but Avanti
withdrew them in 2022.
The last time this journey would have had anything equivalent to Super Off-Peak fares was a very long time ago, towards the start of privatisation. The former SuperSaver fares that BR introduced (the successor to the Blue Saver, I believe) were removed by Virgin Trains when they 'simplified' their range of fares to just Off-Peak and Anytime.