At the mo I have car insurance with a 7 yr no claims discount.
I may be forced to sell my car soon. If I should decide, say in another year to buy a car would my NCD still apply or would I be starting again from scratch?

I think most companies accept NCD as long as its not from a certain amount of years back, e.g. you had 4 years NCD from 25 years ago and wanted to start a new policy with it now. However, I'm not sure how long this 'buffer' period is - I think its 2 - 3 years so you should be safe with 1 year, though I'm not entirely sure and it may even vary from company to company.