The great rear brakes con....

[ddclutch]

So I guess the recommendation is to do a fairly heavy press on the brake pedal every so often. Hard enough to bring the rear brakes into play and often enough to clean the surface. Presumably more frequently in poor conditions when road spray and grit will be thrown up onto the discs.

 

[Bradmore]

Article on the choice between discs or drums on rear brakes found on a website.

There are clear cases where rear disc brakes are the better fit. Vehicles that tow frequently, carry heavy loads, or prioritize high performance benefit from the superior heat management of discs at all four corners. Discs shed heat quickly, they recover faster from repeated hard stops, and they resist fade under prolonged stress.

Rear discs are also common on vehicles with sophisticated stability systems that demand very precise control over brake force at each wheel. Automakers weigh these needs alongside cost and packaging. If the mission calls for more rear brake capacity and tighter control, rear discs are selected. If the mission is quiet, efficient commuting with a strong emphasis on value, rear drums often win.

Looks like an American article from the words used. MG have gone for the more expensive option but unfortunately this is reflected in the cost of replacement.
We have had a good go at this subject. Answer seems to be on EVs to try and use the rear brakes more. Happy Motoring.
.