@Confusedaboutlots; I got my GP text earlier this week, but my DH didn't get one - despite being older than me.
I prompted him to call the GP surgery about it, and it turns out he hadn't opted in to receiving communications via text, which is why he never received one. They allowed him to book an appointment over the phone and have changed his preferences now.
Not sure if your partner's situation is the same, but might be something to check just in case?