Double wear and tear allowance ?

[SYR]

I'm renting out a shop and the flat above to the shop keeper and claim W & T allowance on the rent for flat - for a term of 10 year.

The shop keeper is now sub letting the flat since he can no longer afford to pay for it. Can he claim W & T allowance on his rental income? He is still paying me the rent for both properties and responsible for all the outgoings. He uses a letting agent to rent out the flat.

Is it against any tax rules?

Any advice is appreciated.

[section 44]

Provided that it is a furnished let property, you would each be entitled to wear and tear allowance.