Possible Fuel Starvation?

I had something similar when on a long trip in Spain in the mountains I resolved it by dumping the mechanical fuel pump and fitting a low pressure electric one never found exactlywhatwas causing the fuel starvation

 

^this. I'd swap the coil out as a starting point.

 

Swapped the coil over earlier and we're back up and running Thanks for the suggestion, would have taken me a while to get to that otherwise!

 

My son's T25 has a very dirty brown fuel filter even though recent new tank and fuel lines and big filter, is the tank rusting inside already? Ethanol fuel issue?

 

Easy fix then. Glad you got it sorted.

 

Old vehicle many years of corrosion, change the filter / "polish" the fuel by putting repeatedly rapidly through filtration. as I described.

Ethanol a tiny contribution, but because you have an MGB its also eating out the seat frames..