Are you sure? A boot liner I bought which seemed to be for the lowered floor didn't fit the SE at all.
The Aliexpress ones all seem to fit the Trophy, don't go near them if you have the SE in my experience.
I was looking for the link to the boot liner I have, which was offered in an SE version only, but instead I found this, which seems to have both versions available.
MG Motors UK MG4 EV car mats for all recent versions of the MG Motors UK MG4 EV. Free Delivery over £50. Next Day Delivery Available.
carmats.co.uk
This shows the difference between the SE and the Trophy very well and confirms that the SE is NOT the same as the Trophy in the lower position.
View attachment 24330
This is a different seller from the mats I have so I don't know what they're like.
ETA: Found the one I have, which still seems to be SE only. They also have a two-part rear seat back protector to go with the boot liner, and you can get a bundle deal with a set of floor mats as well as the boot liner and seat back protectors.
* Not compatible with MG4 Trophy & XPower models. Perfectly moulded to fit the boot of your MG4 RHD for maximum protection against dirt and spills. The bucket design ensures everything remains within the boot liner. Waterproof and easy to clean. 3D All-Weather Rubber Boot Mat Can be used in...
evfloormats.uk
I find these to be absolutely excellent. Shame they don't do a Trophy version. However the floor mats do fit the Trophy.