This should be a fairly simple procedure that OVO undertake, but I doubt it will prove quick or easy. You must have a good reason for it (I’m in the same position: PC 02, because I have storage heaters on an E7 tariff. I don’t use them because it’s just too expensive, so I also have a single-rate arrangement). You’d better explain why you want this change: a clear photo of your meter box with its cabling would help; there might be some wiring downstream of the meter that needs changing.

If I were you, I wouldn’t bother. OK, it’s a bit of a pain when trying to compare tariffs, because sites that bother to look at the MPAN will only show plans with day/night rates, so I have to jump through hoops to find what the single rate would be. But because we’ve no idea what the future might bring, cutting myself off from being able to start using the storage heaters again - or charge an EV at cheap night rates -  seems to be a step too far to avoid having to wrestle with two readings each day. That is in itself no hardship at all, because the smart meter sees to it for me.  

A standard SMETS2 smart meter is quite capable of handling two-rate tariffs, so it is theoretically possible to go back from single-rate, although OVO have trouble doing this at the moment. There is no need (although it seems to be the norm) to equip homes with E7 tariffs with meters capable of switching heaters on and off to match E7 timings, sometimes referred to as five-port meters. I feel that they are an anachronism, designed to prevent fraud by running other equipment than heaters on special heating tariffs. 

@neilmcl , one of the things about this change is that there is a barrier to swapping from single rate to dual rate due to an incompatibility in the billing system - that could be why you are currently on a single rate for both peak and off peak. And as Firedog mentions, although there’s the minor inconvenience of two readings to cope with, it is better to have the flexibility rather than not. (I could not add an E7 tariff to mine as it was installed as single rate).
Your new smart meter should also be able to automatically update both registers without intervention so you should only have to check the readings yourself once in a while. 
 

The reason I'm on a single rate is because I asked to be, it was on E7 when there was no reason to be so as I have a gas supply and don't use enough electric overnight to warrant it. I probably haven't been clear enough in my original question. I'm aware that smart meters can handle multiple registers without issue, this is more about changing the profile class to make it easier, should I choose, to move away to another supplier without automatically being offered E7 tariffs and be able to go onto smart tariffs.

Thanks - I think we had presumed your request for a single rate tariff given your current set up. 
What we are saying is that we don’t believe it will be straightforward for OVO to change your supply profile due to limitations on their billing system. That would have been the same reason rather than swapping when you requested a move to single rate in the first place. 

Hey @neilmcl,

Welcome to the OVO Online Community,

BPLighlog is correct, we’ll update the forum if this changes in future. 

Economy 7 to Single Rate 

Although we're unable to physically change the functionality of meters right now. We can offer an Economy 7 to Single Rate plan! This means you’ll be paying the same rate for each register.

If this is something you’re interested in, please get in touch with our Support Team.

Single Rate to Economy 7 

At the moment as it stands, there's no way for customers who wish to switch their Smart Meters from Single Rate to Economy 7.