No! As above, you have a year to complete your course from your purchase date.
The expiry date you have been given is related to the voucher. You have to redeem your voucher and register with us by the expiry date issued on your voucher (following the instructions emailed to you by the voucher provider).
Once you have done that you there is no rush to start or complete the lessons. You can work through them in your own time, and once the lessons are all finished you are free to return to them during that year, in case you need to refer to them at all during your writing.