Lots of possible areas to think about here. I have tried to break them down into the below headings, clearly without seeing you play I can't know for sure which one or combo of the below will help you, but this is what I would look at...
Stance.
Are you side on or quite open, frequently it is hard to play through the covers of you are very open.
Grip
Do you have a traditional grip or are you choking the bat with your bottom hand. This is a very likely cause of some of your ugly shots.
Topple/weight transfer
You mention over striding. I don't like the idea of moving your feet first, I work on the principle that you move your head first to the line of the ball and your feet will move into position. This takes some getting used too, but means that you will get better weight transfer through the shot without hitting the ball too hard.
Hand and head position
Key to playing the shot is having your head over the ball and your hands in line slightly ahead of the ball. This helps your timing and consistent of ball striking.
Timing vs hitting
Given the previous point and what you say about ugly swipes, you have to remember you can't power hit a drive, you time it. Even a bludgeoner like gooch timed the ball through the off side.
Think Ian Bell..
I hope that helps.
Cheers for advice.
I can certainly relate to the trying to over hit and not keeping the head still and level. I think frustration of not penetrating the infield builds up and I try to slap the ball.
Grip, I believe is correct, watched many videos on it. V with the bottom hand with the top hand knuckles almost on top and high elbow.
Stance I have fairly closed. I'm right handed and my left foot is very slightly open and towards the square leg umpire but both feet pointing towards point along with chest.
Problem here being, you going to take this advice, practice in the nets and the next time you come to bat you're going to try and cover drive what should have been a straight drive. Sometimes trying to fix your weaknesses, lessens your strengths.... I've yet to see the perfect technical player in the amateur divisions and all the time you're thinking about what you're doing, you're focusing less of your concentration on the thing that matters most... the ball. Know you're strengths and let you're instinct take over - react to the ball.
Ha listen to me 4 years to get a credible score and I think I'm an expert. Ignore me listen to the experts 
That is a problem with going into the nets against bowlers and really wanting to nail a certain stroke. When it doesn't come you go looking for it. I have done that before.
I guess the main things I know in theory about driving and the cover drive are these.
1.Have you body weight forward, with your head slightly in line of the ball and in just in front of your front knee.
2. Make sure the bat comes down in a nice arc next to your body and not to far away otherwise it wont be straight.
3. High Elbow and keep head straight.
4. When doing your backswing, try to keep your left shoulder lower to the ground while also maintaining high elbow. Allows for the head to come forward and more power from the shoulders.
5. SLightly open the bat face to work it on the off side.
6. Try to make contact with ball at eye level or close as possible.
Having spent some time today doing the cover the drive in the mirror ( Off season down here in AUs) and thinking about about what you all have said. I really think it is mostly where I plant my leg. getting my left leg more out of the way just feels more natural for me and allows the straight drive and leg side shots. So here is my question, for the straight drive I point my left foot towards the bowler and it seems to work. For the cover drive do I do the same or point it more towards cover ?
Thanks again.