I have my son on my policy which doesnt have a NCB as its on one of the other cars, car registered in his name, not a problem with Tesco. It cost a lot less than insuring in his name alone (or even with me added) 1 yr on he has not had a crunch but the NCB is in my name, they wont transfer it. He now has pass-plus which gives him a BIG discount. So that may be a good way forward, its likely that yr 1 may see your boy have a slight crunch, most of my boy's mates have and my daughter had one three weeks after passing her test, so its not exactly unknown, so he may not get any NCB anyway and you'll pay a fortune in his name in yr 1. The quote this yr for my boy with no NCB but pass-plus works out the same as what we paid last yr i.e £1400 TPFT for a Fiesta 1.3 rural area.
Tesco seem very good, Admiral OK. But Mark suggested a while back some insurers are better for certain cars and/or girls/boys etc, shop around obviously. Admiral do a 10 month bonus accelerator too. Insure for 10 months get 1 yrs NCB (hopefully)
HTH
Matt