Android 5.1

My previously very good Moto G upgraded to Android 5.1 recently and it has gone really laggy and slow, so much that I sometimes wait for 5-10 secs for it to complete a simple demand (which was instant before the update) and if I want to use the phone while streaming music via bluetooth then the music cuts out all the time.

Is there anyway to go back to the previous version of Android?

Have you tried restarting it first?

Yup, tried all sorts cleared cache, etc. Still have loads of memory left, I close apps regularly, etc

You could try a factory reset. You'll lose everything unless you back it up.

It'll then take you back to a 'clean' 5.1 version.

You won't be able to go back to an earlier version without doing it manually via PC.