Railways

HS1……

I’m off to Sittingbourne today and I can’t help but wonder whether the average visitor to this country (or resident of this country) is going to find the information:

“On specified AGA trains only plus HS1”

really useful? I assume AGA is Abellio Greater Anglia, which isn’t a name they use now on trains, it’s just Greater Anglia. And I assume HS1 is the section of track between London and Kent which connects to the Channel Tunnel, but it does seem a little confusing to me…….