Where to get prescription inserts made

Dazza @>@'

Hello, I'm looking to get sunglasses with inserts, where is the best place to get them prescripted so to speak?

I'm also looking at what mitchgixer6 has done in one the below by using lenses from his own specs and blu-tacking them to his sunglasses.

viewtopic.php?f=40042&t=12962746&start=40is

borisface

Its in the f-ing thread - www.ciliaryblue.com from £15