This is a quick guide on rebuilding the power steering pump from a V8 Vantage, and I would assume many other AMs from this era. If your pump has a slow oil leak, this may be the way to fix it for $30 instead of shelling out $800 for a new one.
The pump itself is sourced from ZF (now Bosch) which appears to have been used on the Jaguar XF from a similar era or early 2000s Volvos, however neither of which have the same pump, just similar housings from the same mfg.
In rebuilding the pump, I only replaced the seals as mine was fairly new, but in order to save some money, it may be possible to get the PSP from the XF and swap the internals. YMMV.
(1) 2mm X 65mm o-ring
(1) 2mm X 14mm o-ring (optional)
(1) 15 X 28 X 7 metric radial oil seal (TBR or TC style)
The material you should get these in should be Viton (sometimes abbreviated FKM). It will cost more but they have better resistance to hydraulic fluid and a higher temp rating than Nitrile (buna) o-rings. This is critical due to the location of the pump to the exhaust manifold.