So if I'm understanding this right if I have not already got my bitcoin cash I can just send it to the likes of bitrex and will automatically get bitcoin cash?
No.
1. If you had Bitcoin in your wallet before the fork = You also have the same amount of Bitcoin Cash in your address.
2. If you had Bitcoin in your BittRex account
before the fork = You also automatically got the same amount of BCH deposited in your account.
This is all BEFORE the fork. Now, if you send Bitcoin to your BitTrex account you will only see Bitcoins in your balance; If you send Bitcoin Cash, you will only see Bitcoin Cash.