The process to renew your PPL is fairly simple, go to a school and do enough training to pass a Proficiency Check. You will then need a new EASA licence from April next year, so a combined application is called for.
To complete an instructor course based upon a PPL then you need CPL level knowledge before you can continue. You need 150 hours PIC in your 200 hours and 10 hours of IF instruction, an IMC rating would have fulfilled that requirement. You also need to have flown a 300nm X-Country.
There is another option where you could undertake the FI course without the CPL knowledge, but would be restricted to teaching for the new LAPL. Whether there will be sufficient demand to make that worthwhile is another matter. Alternatively, you could become a Microlight instructor.