Nonsense, my good man. Have owned several MGBs, and it was quite common for them to go hundreds of miles between overhauls.
You Sir, are perhaps too hard on a motor vehicle.
One more thing
The dealers Service Manager
Last place to bring a car with sporting temperament. If oneself is not of a technical and mechanical bent, the place to take a MGB is your local farrier. Fitting big ends to mine as we speak.
LOL - best line about MGs ever!
As a postscript, after I sold my MGB, I came "that" close to buying a new candy apple red TR6 with tan leather interior. I absolutely loved that car but a dose of sanity kicked in and I passed on it.