I would stick with your instructor. It's nothing to do with parental habits or anything either - your parents know how to drive and they know not to encourage you to drive like them. But there's a reason why not just anyone can charge for a driving lesson. Remember that with a parent; you do not have the foresight and awareness that an instructor offers nor the safety of the dual controls if you do something stupid. I'm not saying you're as dumb as me, but I bought a car last year to drive with my Dad and I crashed it in less than 24 hours; my Dad was half-screaming at me to brake as he had the knowledge and judgement to know I shouldn't have turned out of that junction at that point - but it was already too late; that is the simple situation of not having dual controls. For reference; I almost did the exact same bloody thing 3 weeks before my test and my instructor slammed down the dual controls and just looked at me like "Mate what are you doing? That isn't like you." "I thought I could make it".
I know the temptation to have a little outside driving freedom somewhat free of charge (Learners Insurance is dirt cheap and I really don't know why, an Adult can't stop you making mistakes as I happily proved) is an extremely attractive concept and for many; I know a few drivers who did 10 hours lessons then 30 in their own car and did fine; but for the sake of safety, thoroughness and experience - pay the extra and take additional lessons with an instructor. Remember that if you have a learners policy out and you have any kind of accident; that follows you to your full license, that one mistake cost me 600 quid on my first premium alone.