i want to rent a property with my parents but they cant get references or pass a credit check can i have the tenancy in my name instead?

Landlords won't let your parents live with you unless they're also on the lease; and if they're on the lease, it's likely they'll also be subject to references, credit checks etc.

you can certainly rent the place in your name only.. But all other occupants MUST be approved by the landlord.  Their income won't be taken into consideration. So you need to earn enough and be 100% responsible for the rent

Your parents cannot live there unless approved by the landlord, and that requires credit checks and background checks.  They are of legal age so they will need to be on the lease.  They are adults - they chose their way of life, so let them find a new place to live on their own.  It's high time you carve out a life for yourself, and your gf, without them.

THey might run checks on all occupants or might not.  I'd just ask if they need to run checks on everyone and if they say they do, then ask them if you could be turned down due to your parents credit problems. If they again say yes, just look elsewhere.

ONLY if the landlord agrees to it & most will not. Most landlords will require all adults be screened & on the lease.  If the landlord does not agree to it then they cannot live there. 

This isn't a yes or no question, because people who rent out houses are different in terms of what they require.  Where rent is concerned, some use the basic formula of salary = 3 times rent.  Others ignore it.  Overall, though, if you and your gf make enough on your own to cover the rent, this should be enough, because your parents aren't on the lease.  The one thing they might require is a background check on any adults living there.

rent the property in your name, simples

If you can prove that you can pay the rent and pass a credit check, I don't see that there will be a problem in the U.K.

You should talk to a letting agent.

Most landlords do credit and background checks on potential tenants.

It only needs the people who’s paying the rent. So if you and your gf are paying the rent then only the two of you would need to pass a credit check and provide reference letters. 

Keep in mind that if your arrangement is that everyone pays 1/4 of the rent and if your parents can’t pay then you two will be responsible for their share of the rent.