Apart from impersonating a police officer, there is no offence of impersonating another person provided you have not gained any advantage either monetary or otherwise provided you have not impersonated them by accessing their computer.
You are in breach of the terms and conditions of the website but they are unlikely to prosecute you by way of a civil claim.
If however you communicate with the third party you potentially commit the offence of misusing private information of the person that you were impersonating even if that was only a photograph. You potentially defame the person if you said things which they would not have said or you led whoever you were dealing with to deal with the impersonated person in a way that person would not have dealt with them, themselves.
There is a breach of copyright passing off in respect of using the image.
The offence of fraud is unlikely to be made out unless there was some kind of gain or intend to make gain and there is also the potential offence of obtaining goods or services by deception.
The police are not likely to be interested but if the victim makes a complaint, and your identity was known, the matter is likely to be investigated in case it was part of something overall which was more sinister.
From what you’ve said however although there may be an investigation (the police are overstretched and) unless there has been a more serious crime committed, it’s not likely to go any further than a knock on the door and a quiet word. To be honest, I would be surprised if it got that far.
Can I clarify anything for you?
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