I can also confirm that I am seeing the same results.
I am with Community Fibre. No other Altnet or Openreach FTTP available. Until recently TalkTalk started showing up on their website only Full Fibre options as they are a wholesale partner with Community Fibre.
It appear that the FTTC packages have disappeared as a result of this deal. Now when I enter my postcode and any address a pop-up box will appear saying..
All of TalkTalk's broadband only plans are data-only Full Fibre. This means they don't include a phone line, and some services that rely on a landline won't work. The below services are not compatible with data-only Full Fibre:
Telecare or care alarms
Medical equipment that uses a landline
Burglar alarms connected to a phone line
Home phone services
The same with Vodafone you cannot choose FTTC or ADSL packages but you can choose landline phone option with Vodafone Full Fibre.
I personally wouldn't choose TalkTalk due to their bad customer service and intermittent outages. Not sure if this issue is resolved with FTTP, but with FTTC TalkTalk was having network downtime even when router was showing as connected.
Also, I read somewhere that TalkTalk does not offer Static-IP address, only CGNAT regardless of which package you select. So, port-forwarding is not an option. But nevertheless, it's good to have the option of switching to TalkTalk but I'd only choose it if there was a really good deal.