Jappo
From your description of the power steering problem this doesn't sound like the usual pump problem. When the gears on the pump fail, they fail. There is no in-between.
You can test the pump by reaching your hand down onto the pulley and seeing if you feel any free play. If you have 1/2 inch of circumferential play then failure is likely soon.
The standard mod is the mini (BMW) electrical pump but this is noisy. An alternative is fitting a replacement mechanical pump but after some modification to prevent further. I know of a Morgan dealer who has gone down this route with success.
For info my car has 39000km and no excessive play yet (famous last words) on the pulley so the problem does vary from car to car.
Cheers
