It may depend if you get another job quickly and they are willing to take on some the cost of the NVQ - some employers would ask the new employer to pay a proportion for you, as the new employer will be the person benefitting from your new qualification in due course. What you do need to do before you leave is to ask for any completed units to be signed off, because then your NVQ provider will be able to give you some written proof that you have completed those units. If you can't carry on but you can start the NVQ again later with a new employer, you should be able to credit those completed units so you don't have to start from scratch again (but there is a time limit to how long people like City & Guilds will take this into account).