Thanks for the comments folks. Had parents evening at school tonight and made him sit in on the discussions with the teachers who all said he was well behaved and very clever but just very lazy. I just find it extremely frustrating as I am a worker - and yes I know he is not me! Just need to keep the heid and work on the patience a bit more. He does seem to be a bit more biddable today...
It sounds very normal, motb. Remember he's got to manage to grow up, become independent and leave home over the next two or three years. The defiance is a normal part of this process for most teens - they can't work out their own solutions to problems while their parents are telling them what to do! You don't want to be constantly on his back about studying - so don't be! Try backing off, and letting school deal with him if he doesn't do enough work.
Sounds loke a typical 15 year old tbh. My own Ds is in year 10 and can be lazy, vague, stubborn however he is studying mechanical engineering at college 2 afternoons a week, since he started he has been studying harder with other lessons but only because he needs to so that he can stay on the course. He is currently working above his estimated target. I have asked him what the big change was and he said he liked the way the college tutors spoke and acted towwrds him, once he was handed the responsibility of his own future (ie they are given the responsibility of their own learning at college) he seems to have grasped it with both hands and ran with it. I think because he had to pass an entrance exam and an interview he was extremely proud of himself so has made the most. Is there any chance of your Ds getting any incite, work experince into his chosen path, maybe this would be a motivation for him. Other than that extreme patience on your side is all I can offer as advice.
My son is reasonably well behaved most of the time. He is lazy, and needs to be asked loads of times to do chores. His school report is decidedly average for a very intelligent child which is disappointing. I have tried to be patient with him and suggested if he does not want to study and school is not for him, he should leave as I am not prepared to have to constantly be on his back re homework and studying. He says he does want to go to university, but doesn't seem to put the work in. My main problem however is that whenever he doesn't want to do something, he just stubbornly refuses to do it. I wanted to help him prepare for an exam tonight and he refused to read it out to me, saying he couldn't be bothered. I eventually lost my temper, and am not proud about that, but just don't know how to deal with a boy who just will not do what he doesn't want to do. I have taken away his gadgets, and told him he has to earn them back. Any suggestions or advice gratefully accepted. Very frustrating