Do I need to cut my Lavendar back for the winter, and is so how much?

what is your location

Nope, you don't need to cut lavender back for the winter, it's wonderful like that! Just remove any dead wood and trim back any places that you think are overgrown. One of my lavenders is close to a pathway and I trim it back when it hangs over it. The others I only remove dead branches. I have around 12 different varieties and treat them all pretty much the same. Enjoy!

No. Save the heavy-duty pruning for spring. Instead, you can use this time to improve their lot: add mulch to protect them, improve the drainage in the bed, divide the plants.

Pruning woody stems left with no green growth.

http://everything-lavender.com/lavender-care.html#Prune

Here you go, my fave lavender site!

http://everything-lavender.com/when-to-prune-your-lavender-plant.html