I walked Carmino Norte from 4/23/22 to 5/27/22. I used backpack delivery services by "Trans-Mikel" from Irun to Bilbao; he charged me 50 Euros for 7 stages. From Bilbao I used different "Trans-Mikel" who charged me 20 Euros for each stages because I was the only one customer. He tole if he has another customer, he will charge me 10 Euros. I know it's very high, but I had no choices due to have back pain.
At Castro Urdiales, I had Correos information, I arranged Correos services from Laredo to Santago de Compostela; total 25 stages. I paid 169 euros at the beginning (They gave me some discounts).
Correos has English speaking person, and they are very helpful. They work until 8:00 PM, so whatever I had any issues of delivery, they answered my call all the time and solved the issue right a way. I like their services.
When I walked FC, there are many services available like JacoTrans, etc., but Camino Norte has not many choices. I think Correos is the best on the Norte.