Hello,
As a driving instructor I felt I should probably give a little reply. I can see many people have made you aware of the outrage of having to cover the cost, but there are multiple things that should be taken into consideration.
How long have you been learning to drive for? Are you experienced enough that you shouldn't be expected to go up a curb? If so, The driving instructor shouldn't have to grab the wheel to avoid such a situation.
Did your instructor get you to sign a disclaimer when you began lessons with them stating that you would be liable to cover any minor damage due to negligence? If not, You have a leg to stand on.
I as an instructor weigh up the odds, If you are a new learner and do not fully understand the full controls of the vehicle then I am expected to cover you in these circumstances..
But, If you've had 20+ hours and are fully aware of where your distance should be from the curb, I as the instructor should make you aware you're getting closer to the curb for you to fix the situation yourself, and possibly grab the wheel to protect the vehicle from damage if you're not correcting it yourself, but many learners also steer towards the opposite direction as natural instinct when an instructor grabs the steering - if this is not successful then £50 for a tyre is a fair price. My tyres cost £65 each from Ford - If one of my experienced pupils hit a curb to the point it shredded, Then I would ask them to cover the cost too - Only because they should already know better and that's over 2hours working hours for us to replace that tyre. But, Like I said, If they're a new learner - They dont know any better and I should of been more aware of the situation.
Take from this information anything you like.
As for his lack of MOT - That is a seperate issue entirely and therefore his vehicle should not legally be on the road. Although this is a situation he has put himself into, It does not detract from the tyre situation. No instructor I know would claim for a tyre through the insurance company either.
If you feel you would be happier with a new instructor then you need to make the decision that is correct for you, But do not feel as though he is wrong for asking for cover of damages if you are an experienced learner.
I hope this helps to see a little insight atleast?
Best of Luck,
TriixRose