Is the British NVQ Diploma valid in italy..? Please help!!

you should go to a centro di formazione professionale like this one: http://www.gestcfp.com/preiscrizioni40/ and ask a teacher there. (go to more than one - and ask to speak to an english teacher. compare your syllabus with the school's)

your qualifications should be valid and might be equivalent to a diploma professionale di tecnico which students attain at a CFP when they are 18/19 years old. but check for yourself!

good luck.