I have just replaced the heater bypass assembly - all hoses and the "cheap" plastic 4 way tee. Fortunately the disintergration occurred close to the mechanics workshop but the replacement was a bastard of a job. Also the push on terminal for the starter motor solenoid "came off" and what a nasty thing to get back on.
I also have a 1964 MGB which I have owned for 25 years - much simpler to work on and I do feel more mechanically safer with it. I recently drove 8500 kms in it from Tasmania to Western Australia - ferried from Tasmania to Victoria.
Any comments from MGTF owners would be appreciated.