Yes, but no.
Only had the policy for 2 months, so that's all it's delayed my NCB. (Won't get a years NCB until Dec 17 rather than Oct.)
I think even if I'd missed out on a full year the saving would off offset any NCB discount.
Plus the renewal is just after the date I passed my test, so there's a benefit for driving for a full, rather than partial, year longer.