It is quite official that the MG5 replacement will be an estate version of the MG4. It is due around the end of this year but timing is less certain.
MG are changing their naming, if you look at the naming they are using with their EV ranges (not petrol), their IM brand and the forthcoming 9/S9 and this, then a pattern is emerging:
- Number denotes size
- 'S' denotes SUV version
Therefore the new MG ZS is the MGS5, being the SUV version of their new '5' model, which will sit alongside the MG5 replacement (both being on the new EV platform pioneered with the MG4), which is why I am suggesting the new MG5 will still be called MG5 and not MG4 Estate - my guess is that they won't make a separate 5 from the 4 Estate.
There's plenty of room below the '3' for smaller cars. The 6/S6, 7/S7 sizes are being defined in the new IM range and the MG9/S9 cap the large vehicle range.
Older petrol platform cars may keep the same naming as present, so you may still be able to buy an MG ZS with a petrol engine, alongside the MGS5, but it will be a different car on a different platform and we still have the HS.
I may be wrong, but this is what I see.