Regardless of what the car is worth or value declared, you must receive a payout to cover costs of repair to return the car to before the accident. If you're at fault and claiming through your insurers then yes they can turn around and say you only insured it for €xxxx so that's all we're paying. However this was caused by someone else so why should you be out of pocket?
Your insurer is perfectly entitled to payout to you and pursue the uninsured party at fault to recover costs. It's their own fault for driving uninsured. You're also entitled to pay to fix your car and pursue the party at fault.