Hi. My name is*****'m looking at your question now and will post my answer or ask for more information here in a short while.
I have you letting the property for 21 months which covers £29,167 of the gain. The letting relief is, therefore, £29,167, the lesser of £40,000, £41,667 and £29,167.
PPR is £41,667 and letting relief is £29,167. Annual CGT exemption is £11,000.