Hi pines & welcome to the forum.
You have obviously made a few changes to the car with a view to “track use” Without the benefit of being able to look at the car & consider the changes a definitive answer is unlikely.
For your benefit, I have copied the relevant information from the testers Manual to help with your question. However, from your post I would advise that in my opinion it would not be exempt from requiring functioning airbags and warning lamp. Removing the bulb to get around the issue come MOT time is just placing the tester in a compromising position.
From the Manual…
If a vehicle has been extensively modified or converted, certain defects, such as for components ‘missing where fitted as standard’ should not be applied, for example:
a car converted for competition rally use must have the rear seats removed, be fitted with a roll cage and full harness seat belts, may not be fitted with components such as brake servo, power steering or airbags, a car converted to a stretch limousine may no longer be fitted with items such as curtain airbags or a functional electronic stability control system
This exemption does not apply to vehicles with minor modifications. Therefore, a car fitted with rally style seats, body kit and a sports steering wheel would not be exempt from the requirement to have a driver’s airbag if one was fitted as standard equipment.
