The MGB oil pan reinforcement plates will stop oil leakage from the front and rear of your 5 main bearing oil pan.
The front and rear are more susceptible to leaks for two reasons:
The oil returns from the front and rear main bearings are just inside the pan so there is a constant flow of oil in these spots.
The rear part of the pan below the rear main bearing has only a thin part of the pan pressing on an equally thin section of oil pan gasket. This compounds the problem.
Add to that the very thin sheet metal of the oil pan itself often leads to distortion especially if the mounting bolts are over tightened. The small ribs between the bolt holes do not transmit the pressure of the bolts to the surface between the bolt holes leaving gaps for oil to seep through.
The MGB oil pan reinforcement plates are 3/16” steel plates fabricated to fit on the front and rear of the oil pan.The main picture on the listing shows the plates and included hardware.
I bought their timing cover reinforcing plates which cured the leak i had ………. see https://mgb.tips/2019/10/20/mgb-timing-cover-reinforcing-plate/