Update on the dice:
Sealing them works. The print will scratch off if you really try to scrape it, but it's not going to chip or fade from ordinary use.
I'll be taking a look at postage costs for sending some out to people unable to make it to the event.
Don't forget, if you do want them personalised in some way to let me know asap. I'll be printing these up last weekend before Oldhammer day, so I need to know by the end of next week.