BruceTF135

The car in the video is definitely smoking too much.  It doesn't sound good so is in need of some attention.  It sounds like the garage that you have been using are not, shall we say, able to fix it.  You really need some EXPERT help.  I agree with what others have said; get it looked at by one of the many MG / K series experts out there.  Depending on where you live, here is a list of suggestions.  Most are mobile so location is not the limiting factor.  In no particular order:
Rough Luck Racing
MG Rover Mobile Mechanics
MG Rover Solutions
MJS Auto And Marine
There are many other decent garages that understand the MGF/TF very well.  Provided with your location, I'm sure that people could make suggestions.  I'll start with my local area, SE Essex, with British Legends in Southend-On-Sea and MG Rover Repair Centre in Wickford.
Good luck