How do I move energy suppliers when I have an exotic meter with OVO?

I’m not sure if you’ve noticed but there have been some recent announcements about that type of meter set. 
As far as I’m aware, no other supplier currently supports those meters 

Yep I have seen, but what is the process that I need to go through to move suppliers? Can I get an electrician to remove or replace the meter or is that down to OVO? 

As the guide suggests, depending on exactly what meters you have there are options to ask for a smart meter change or await details from OVO for the next step. 
All details are in the guide I linked above - a ‘standard’ electrician is not allowed to change meters

So to change the meter with the intention of changing supplier I have no other option but to go through OVO for them to change the meter? 

Correct. Only the active Supplier can do this. And even then, we cannot promise that other suppliers will take you on anyway.

I tried to leave a few years ago I went to The Cooperative but they said they couldn’t support my meter and I needed to return to SSE, could they have replaced the meter when I was with them or were they right to send me back to SSE. They said that only SSE could charge it? Was this the right information? 

Not surprised there - but the info was correct. If that supplier rejected you (oh, and they no longer exist btw), then you’d have been bounced back - SSE would have had to do it.

As mentioned, if the supplier won’t take you on, they won’t touch anything. Additionally, the Co-Op would have never had the required resources to swap such meters anyway.

Sorry, just to clarify The cooperative couldn’t change my meter it had to be SSE?
 

If that was the case why couldn’t the cooperative change it? 

Because ultimately, the required meters to swap it didn’t exist back then - Co-Op definitely didn’t have access to anything suitable, I know that much. And IIRC hardly any supplier other than SSE and Scottish Power knew much about most RTS Meter types.

They took me on for two years, but could never get the billing to work properly so they sent me back to SSE in 2015 and advised me to ask SSE to change the meters. They did change them for exactly the same set up - but new meters. They changed the meters in 2017, so smart meters and eco 10 were available then.