Deposit deduction for burns on carpet

Hi,
My tenant has left the house clean and in good repair generally, he even has repainted the all the walls and part of the ceilings where necessary.
However after he left i removed the bed and noticed he left on the carpet some stains and a couple of sigarette burns.
How much would it be reasonable to deduct from the deposit?
Thanks

If you have a cut of carpet that can be repaired by a carpet chap for £30-40

If its under the bed, I’d probably let it go if they were a good tenant