Most cars have teething troubles though it would seem MG’s have quite a lot.
We have a MGHS which luckily has minor issues such as every now and again the electric boot stops half way or the info mat system freezes reboots.
Our local dealer also used to be Mitsubishi (our last vehicle was a Outlander) now MG and we found them to be excellent one of the reasons we went for the HS, they have been very good also in regars to the MG though we have not had it back yet with any issues will see what happens by the time of the first service.
I did however get the impression talking with various people that MG motor doe things differently and there are a lot of unhappy owners on the forums that cannot get there car repaired quickly and efficiently which does worry me as I was considering purchasing a MG4 privately.
MG’s have a 7 yr 80k warranty which should cover most things and I would be very annoyed if I was asked to pay £120 up front for a diagnostic check on something that turned out to be a warranty issue, it should be the other way around it always was when I worked in the industry.
Someone mentioned dealer servicing for the warranty, since the block exemption rules you no longer need to have the vehicle serviced by the dealer network but can take the vehicle to any reputable garage as long as long OEM or equivalent parts are used, many people prefer to use the franchised dealer for peace of mind.