Selling section 23 after 9 years 8 months

[rabbit]

If someone sells a section 23 apartment after say 9 years 8 months, is there a clawback of tax relief ? If so, is it only a 30th of the original tax allowances ? ( the proportion 4 months is out of 10 years ) ? All of the tax relief was long ago used up. The current tenant is moving out and is it necessary to wait another 3 or 4 months to sell ?
Thanks in advance for any replies....someone may have practical experience of this situation here.

 

[Purple]

AFAIK it's the whole lot.