I need legal advice on taking EON to court.

[Deleted User]

If you read the posts above you will see that you have been offered advice which is why you should either talk to a solicitor or Citizens Advice and they will be able to tell you whether you have a case that you could bring against E.oN. Posters, with no legal qualifications or sight of all the evidence, are reluctant to offer legal advice. We are not talking about a lot of money here,  and a frivolous case brought against a supplier could leave you significantly out of pocket. 

https://www.citizensadvice.org.uk/law-and-courts/legal-system/small-claims/

rp1974

Uncertain as to why you need to or want to retain this type of metering which will mean your paying high prices for your usage whatever your supplier is,you should look at getting your meter switched to credit mode,as it's a smart meter it should be able to be done remotely.
After that's been done you will have access to any supplier you choose.

As regards EON,only thing I can see would be following their complaints process,again,if no change request a deadlock letter then refer to the Ombudsman,again.

It's unwise to follow any legal advice offered unless it's by a qualified person,could be costly and achieve little or nothing,as was suggested earlier Citizens Advice would be a good place to start.