I lost my gles, do i have to pay the full price for specsavers to replace them?

I recently got some gles from Specsavers. Im under sixteen so i got most of the cost paid for me by the NHS. This was around 5-6 months ago. But i somehow lost them recently and my vision seems to be getting worse & i have headaches all the time (presumably from straining my eyes). Will Specsavers replace my gles for free or what?