Sorry for the loss of your coins.
I had my bitcoin on computer hard drive for 3 years but was advised to put it in a safer place (blockchain.info wallet).
Whoever advised you to do this is an idiot. Web wallets are the least safe type of wallet in existence, and blockchain.info specifically is a terrible web wallet. Are you sure the person who advised you to do this isn't the person who has stolen from you?
Set up a paper wallet and traded for a week or two and one day last week I went to my access my wallet as always and was asked to confirm if I was using a different computer to access the site
I'm not exactly clear here what wallet you are talking about? A paper wallet with a private key? Or your blockchain.info wallet? Did you import a private key from a paper wallet to blockchain.info?
I had passwords, used the Step 2 safety check can somebody let me know if there was more could I have done??
If there was malware on the device you used to log in, it could either have stolen your password and 2FA codes in real time, or even processed the transaction in the browser after you logged in without your knowledge.
I did notice that my imported address still showed my private keys (I know this may sound a bit obvious to you crypto veterans) but please can somebody tell me if this would have been visible to anybody who could have hacked my account?
Yes. If you import private keys in to blockchain.info, then anyone with access to the account has access to the private keys.
I have not managed to gain access and it is now not accepting my password.
Do you have your 12 word seed phrase backed up? Use it to restore your wallet somewhere else and move all your funds out of it.
or is their something Blockchain.info are failing to accept blame for?
There could well be. Their platform is completely closed source and we have no idea what their security set up is. I lost count a long time ago of the number of users who have lost coins to blockchain.info. They should be avoided at all costs.