I've used temporary insurance to borrow my inlaws 4x4.I used www.dayinsure.comBasically it's £10 per day (plus admin fee) for any car upto the value of £40,000 for fully comp (and you can add additional drivers for free).You can set the time your cover starts (ie immediately for picking up a car or a week in advance). Doesn't matter about NCB or points.They will insure cars over £40k but not sure how much for.Well worth a look.