DRC isn't specific to any one retailer - if a fare is from or to a station, then its CRS code is used on the eTicket. If a fare is from or to a fare group, like Dorchester South or Dorchester West, then there is a list of "fake" CRS codes to use for the group. LON for London Terminals, BIR for Birmingham stations, MCR for Manchester stations, DRC for Dorchester group, and so on
Above DRC it should say "Dorchester South or West" (very specifically it should be this string), as that's the fare location name that matches DRC. Underneath you'd expect to see the itinerary which will always be to a specific station rather than the group.
For example a fare from the group should look like this (mine is a red specimen ticket rather than yellow but it's otherwise the same):
The fact you say it's an Advance, and you say it looks like it just says "Dorchester South" is intriguing to me. There are no Advance tickets to the group I can see, they're all fares from Dorchester South explicitly. So how you've got DRC on it I don't understand.
It would be interesting if you were happy to share it (without the barcode and if you'd prefer with any dates or times redacted is absolutely fine)