what he said though you can get a book for a tenner on the test and you can get the test online through dubious means
FWIW the ecs card is for TRAINED and QUALIFIED staff
To be recognised as a qualified installation or maintenance electrician in the UK, you have to have achieved an electrotechnical NVQ Level 3 (or its equivalent), which entitles you to apply to hold an ECS gold card
He is not so he cannot get one anyway
CSCS card is required for building sites but not domestic properties.
I am not sure he technically needs either for centreparcs and I suspect the employer just needs to be sure your son has done some basic H & S prior to starting work.
CSCS may meet this requirement but it is not specific to electrical risks so it may not
I agree with call both and see what they recommend as there is certainly a trainee CSCS card. I know little of ECS as it is for qualified staff
I strongly recomend you son trying to do his NVQ whilst there and other tickets as required Part 18, PAT etc