Can a Spanish speaker help me with this allergy card to show restaurants in Spain?

[KimGa]

Last time we holidayed in Menorca we struggled to get waiters in restaurants to understand when we tried to tell them about our son's nut allergy as we don't speak Spanish fluently.

Next weekend we are travelling to the Costa del Sol and I have since discovered allergy cards exist that you can show to a restaurant. I want to create my own. I have put my English wording into google translate but I wonder whether someone could kindly check sense-check the Spanish for me?
Mi hijo tiene una alergia alimentaria grave. Para evitar una reacción alérgica potencialmente mortal, no debe consumir ningún alimento que contenga frutos secos.Por favor, confirme que su comida no contenga frutos secos ni derivados. Asegúrese de que su comida se prepare con utensilios y equipos limpios para evitar la contaminación cruzada. Gracias.
I am hoping it says:

My son has a serious food allergy. To prevent a life-threatening allergic reaction, he must not any food which contains nuts.

Please confirm his meal is free from nuts and nut products. Please ensure his meal is prepared using clean utensils and equipment to prevent cross-contamination. Thank you.

I Lived in Spain 2000-2007 and have family and friends there.Go over several times a years as my one of my sisters and one of my step brothers relocated
Im going to be brutal here. The translation is fine , appropriately formal and clear
HOWEVER
If you are eating in large cities/ big touristy towns great but if you are venturing off grid into small towns a villages the idea of cross contamination and derivatives I wouldn’t be so confident that my child would be safe. It’s just not on the radar, alongside dairy intolerance , gluten free etc
My DH is vegetarian and still gets served fish/fish derivatives like anchovy in a sauce even tho we say etc

Spain uses the 14-allergen system like every other EU country. Restaurants that cater to tourists typically have menus that show all of the allergens in any given dish with their numbers in parentheses. Peanuts (ground nuts) are one category (number 5), tree nuts (including walnuts and pecans) are another (number 8). See curso-alergenos.com/lecciones/los-14-alergenos-principales/

Also, walnuts and pecans are not widely used in cooking in Spain. Maybe in cakes and salads, but they will then be listed as an ingredient (they are both usually called nueces; pecans might have the word "pecan" too). They are not going to turn up out of the blue in almost any dish that you might order, outside perhaps of a fine dining restaurant.

The card is fine, but waiters are busy and might not know what to do if you just hand it to them out of the blue. You might want to learn to say "tiene alergia a las nueces" (tee-ENNEH all-air-GHIA ah lahss noo-ESS-es") while pointing to DS. You will be able to gauge from their reaction if they take these things seriously. The bigger the place, the more likely it is that they will. (And the more likely that there will be someone who speaks English well enough to reassure you.)