Can I ask how old you are and who owns the car? Do you live with your parents?
The thing with experience is that you're not going to actually get any unless you're out there driving! You have been tested by an independent examiner and they have deemed you competent to drive. You have a licence, I presume are insured to drive the vehicle, and are an adult, therefore it really is up to you.
When I first passed my test, I actually made a point of going out and driving on my own as much as possible in a variety of conditions. Good weather, bad weather, country roads, city centres, motorways, short distance, long distance... I took my time but I did it... and it boosted my skill and confidence so much because no situation felt scary or difficult after that. Yes you will find yourself sometimes feeling slightly challenged in certain situations but I found that taking myself out driving without anyone else interfering or pushing their own driving fears onto me, I learned to become a confident and independent driver very quickly.
An hour journey isn't long - I'm sorry, but it just isn't. Nighttime motorway driving... it can actually be safer in some ways because there's generally less traffic on the road. It wasn't lots of dark winding country roads where you can't see anything. It's important to get comfortable driving in different conditions - you don't want to be one of those drivers who is limited because they "can't drive on a motorway" or "can't drive at night" - not for any medical condition - but just because they've never done it and are consequently scared to!
I think you need to take back a bit of control on this and not have other people dictating to you when and where you can drive. If it's not your car, that does make it a bit more tricky, but, presumably the owner has been happy for you to be insured to drive the vehicle. Your parents at some point have to trust you to go out there and drive. It's the only way you will get experience.
Just out of interest - what were their actual concerns about the journey you undertook? Are their concerns overall reasonable or are they actually very nervous drivers/passengers who are overreacting and pushing their own fears onto you. The latter can actually make the experience much more stressful for the driver and could in fact be hindering your progress/confidence.
Do you know any other people who are really into cars who could go out with you and give you useful confidence-building tips rather than restrict you from a fear perspective? That could be helpful. But seriously - I think getting out on your own as much as possible is actually the BEST thing you can do; you HAVE to deal with whatever comes your way, you get lots of experience and you learn faster.