It doesn't make that much of a difference or it didn't in my case, I assume they have become wise to this sort of thing.
First year it saved me £100 but second year they actually wanted £175 more with my dad who has the maximum no claims bonus which I found bizarre.
23 as a new driver £900 on a 1.4 in a whats considered to be "high risk post code" and now onto the start of my 2nd year with 1 years no claims discount I managed to get it for £600 which I was really pleased with especially knowing what some people around my age pay!
Interesting though, it was only last night I got a quote for my current car and also a quote for a Golf with more than double the power of mine and the golf was only £50 more expensive to insure

about 16 insurance groups higher!!