Did a bit of a search and there are quite a few options, this one looks the best and most effective, it’s also the largest and most expensive of course.
Trans filter
I’ve no experience with MGs fitted with a CVT ( I’ve avoided them like the plague as most CVT transmissions fitted to cars are rubbish, they can’t handle much torque, the fact that MG detuned the engines for use with the CVT, should be an indication) but I have much experience with normal automatic transmissions.
You would fit this in the feed line of the trans cooler……if fitted, if these cars don’t have one then no, this won’t be the solution ( if they don’t have a trans cooler, no wonder they blow up all the time!)
Normally trans fluid is filtered before it goes through the transmission, but using one of these you’d be filtering in afterwards, not ideal but better than nothing, if you can no longer get the original type filter.
You’d also need to modify the original filter pick up by removing the filter media and probably replacing it with some mesh.
A job for those with mechanical aptitude only.
The reason you’d need to gut the original filter is that old clogged media will inhibit the flow, and as the original type filter is part of the oil pick up you can’t just leave it out.