Topic

It's quite likely the topic has been covered but if it's not in the pipework, let me share my experience.
I have a 2005 MGTF 1.6 in Starlight Silver, purchased back in 2014 with just 28,000 miles on the clock. Cherished and loved car.
Recently experienced the electrics going silly, on a recent run suddenly ABS light starts glowing followed by the SBS light displaying, Speedo drops to zero,
Mileage meter flashes and dissapears, rev counter bounces. No loss of power steering and no problem with the breaks.
Having left the car for a couple of hours, she started first time and remained calm for the journey home. Having arrived, I turned off engine then tried to restart it.
Nothing, completely dead. Lights worked, heater blower worked, windscreen wipers worked. Tried to restart, got clicking form the starter motor and engine attempting to fire up without success. Now many have said it's the classic signs of a faulty alternator. Before you shell out for a replacement, you need to check something out. The Ignition barrel and connecting leads. I removed the cowling and started pressing the connector block. Turned ignition on, car started with no hesitation. I then applied the unit with quick drying electrical contact spray. I'm no longer getting issues. I've left the cowling loose just in case it plays up again. Hoping this is a permanant fix. I'll keep you posted.

The ignition switch contacts can be problematic when they decide to act up. I had a 135 which I bought new in 2004 and had to have the ignition switch replaced - hence a new lockset all round by a local MG dealer about 24 months after I bought the car, sadly no warranty claim due to the demise of MG-Rover. The symptoms were exactly as you describe. Fortunately there is a good source of second hand lock kits about if yours does decide to pack in!

Sundance

Some of those symptoms can also point towards failing earths, diff to rear bulk head and inner wing to battery.

Cheers, will give the electrics a good going over.