It should offer you GroupSave as one of the fare options by default rather than having to request it as a railcard.
I'm delighted that it now does this. Even gives you Groupsave for 2 adults + 1 child.
There is the (much more minor) issue that some customers read the resulting prices as
per person and panic, not realising that the price is for the whole group - "You told me £17.50 each but the web site quoted £33.60 - and for three of us that's over £100 ..."