I contacted Motability this morning by email and within an hour, I had a telephone reply /conversation confirming that I could extend my lease by up to two years , and this is now on my file, ready for the date in the new year when I will receive the renewal letter .
In the eMail, I had confirmed the mileage , currently 18000 plus, and the extras fitted , and that the Tiguan SEL suited my needs.
It was overall, a very painless process.