The steering pump used by Morgan is a low quality punp from Mini. I've seen mechanical high pressure hydraulic pumps last for hundreds of thousands of miles on cheap Citroens, so you might be better off and safer with a different brand of steering pump.
That being said, you might want to follow the general rule of "if it ain't broke, don't fix it".
To make the pump last longer, avoid steering at standstill. Standstill steering puts a lot of strain on the pump.
Harald