Covid negative test certification

Hi all, hope all are well, I have just found out that Gatwick airport south terminal carpark are carrying out covid test for staff and travellers for £60 and £90 for the general public, but says you must check with airline if spain  will accept the certification. Called Ryan air and all they say is we don’t know call the Spanish embassy, so non the wiser,  sent Gatwick a message to see if paying £60 will allow me to fly on 14th December, will update you all when I get word back in this issue.