Im 25, 2 years ncb, clean licence and just renewed today on a standard 172 with elephant - was going to be £760 but I got a quote of £560 from admiral if I put my 26 year old GF on as a 2nd driver, or £690 with me only. Its unreal how adding a person brings my policy down!
In the end elephant matched the £560 admiral quote - theyre sister companies. Great service from them. You can also play around on their website, adding mods and see how it affects your policy.