posting equipment

Yes, check out the Casa Ivar front page: http://www.casaivar.com/
or Express Bourricot https://www.expressbourricot.com/luggage-transport/

And me with Ivar, on several occasions.
Regards
Gerard

Coming from France, many of us will highly recommend Express Bourricot from SJPdP direct and securely to a locked room at Albergue / Hostal Lasalle in Santiago. You send one suitcase or duffel bag, contiang stuff you do not want until you finish, and perhaps souvenirs bought at SJPdP, ahead to wait for you.

Not cheap, but very safe, secure, and reliable. Multiple people can share one bag to keep costs down. Check their website for specifics: http://www.expressbourricot.com/en/

Once you are in Spain, the best way to send things forward is to use the Paq Peregrino program at the Spanish post office (Correos). It is relatively cheap, fast and easy. If you use their app, they have tracking service too.

Hope this helps.