This is the response from Blockchain. I re-iterated that I had the original email address and would like the current email (which i don't recognise) to be changed back:
Hello,
Thank you for your message and I am sorry to hear about this. If there is an email change that may have performed in your account that you do not recognize then your account should be considered as compromised and it should be no longer used.
Unfortunately, we are unable to help recover or reset passwords, nor can we change back the email address of that account. This is not a matter of policy; this is due to the very way the file encryption is designed. If you’ve forgotten your password, please try every possible password combination you may have used when you created your wallet, bearing in mind punctuation and capitalization. If your account was compromised, then I am afraid that this is likely the reason you are unable to access it.
If you backed up your wallet using its 12 word recovery phrase, then you can recover access to your account by clicking here or by clicking "Forgot Password" on the mobile app. If the "Continue" button is inactive or you receive an “Invalid Recovery Phrase” error, then the recovery phrase submitted is inaccurate.
If you do not have the correct password or an accurate recovery phrase, then access to the wallet and any funds contained in your DeFi Wallet have been lost. You can read more about how our wallet works here: How it Works | Blockchain's Non-Custodial Wallet
If a wallet becomes compromised, it should not be used to hold funds. You can visit
https://login.blockchain.com/#/signup and create a new wallet with a new email address and a new, unique password. Before sending funds to this new wallet, complete all Security Center steps under the Basic tab. This includes verifying your email, enabling 2FA, and making a backup.
I have no idea what to do now. Looking back at my emails from Blockchain, I had the confirmation of account set up straight away. Then in 2017 I had an email asking me to confirm my email (I can't remember seeing this at the time so I assume that I didn't) Then finally I had one in 2018 which was a news letter. If the account has become de-activated, would it have been linked to another email address? Any ideas what to do?