Its worth it just for the motorway tuition, seeing as there is a silly rule that means the first time a new driver will go on a motorway will be without the instructor!
Another option would be an advanced driving course with someone like the IAM...it would probably be best to speak to them though as she would need to be able to drive confidently enough to take on board the additional stuff, but early enough to have not got into bad habits.
A lot of it is real basic stuff that should really be in the test, such as when waiting to turn right across oncoming traffic, keep the wheels straight. Angling them or the whole car in order to be able to nip across quickly just means that a relatively minor shunt from behind turns into a major side impact as the car follows the front wheels and you end up across the other lane.
Another one that springs to mind, is very few people are aware that the 'blackspot' warning sign that is no longer in use was replaced by the grey and yellow backgrounds that frame a warning sign. Grey means there have been something like three serious accidents over a certain timeframe, yellow means there have been in excess of a certain number of accidents. Just to prove how unknown this is, I can't even find reference to it on Google! Similarly, the skid warning sign doesn't normally mean slippery road, it means that accidents have occurred where a car has skidded under braking. That's why you see them even where they have laid down the abrasive cream/yellow stones as an anti-skid surface.