Are the one’s you’ve got completely shot, or just muddy? Yet to have my Hope ones wrecked on the big bike. Just had one service by me taking them out, pulling the seals and cleaning them balls 😀 (and regreasing of course). Good as new now.
As for what replacement fits, I don’t know. Will depend what size and type of headset it is to (straight 1 1/8, tapered, 1.5 straight, integrated, semi, external, etc).
But Superstar do some bearings. Not sure they fit Hope but maybe. £7 got me a couple of 1 1/8 and another £7 for a single 1.5. That’s for my hardtail, not Hope on it though.