Keith & Carole
If you are refering to the recent posts on the YBW forum about being able to change the shaft seals without actually having to remove the pump housing itself then I do not believe this is possible on the volvo engine.
The pump housing has to be disengaged and taken off so that the shaft can be removed from the housing, and to do this the locking nut is on this engine side of the housing and shaft.
The seals themselves are then retained by circlips and again the oil side seal necessitates the removal of the shaft and housing.
Taking the pump housing off is a simple matter but you will probably require a vice to hold the impellor end of the shaft to remove the locking nut.
Replacing the seals is then pretty straightforward but make sure they go in back to back. Similarly re fitting the pump housing is simple once you get the cogs aligned.
Also check for wear on the shaft when you replace the seals. If it is worn then for the sake of approx £10 you can buy a new shaft.