Check out Bosco Bear, Identikids, Identity Direct, Stuck on You, Mooo (yes with 3 O's). I have used Identikid in the past, initially can be expensive for the packs, they work out good value in the end as I am still using the pack I got for DS1 in Prep now, he is about to go into grade 3. So good value really.
A dymo would be a fantastic investment!!

ETA: Someone I know has ordered through Bosco Bear recently and said she is still waiting for her order that she ordered a few weeks before Christmas.
Just make sure you check delivery time