Rover 25 2.0 Streetwise Diesel Oil Leak

[Spydaman]

My daughter's Rover 25 has developed an oil leak which has caused the auxiliary belt to fail. She's had that replaced but has been advised that the crankshaft seal is leaking and will cost £400 to replace. This seems a bit steep to me if it's just the seal costing £15. A bit of research suggests it might not be just the seal but could be the oil pump leaking. Is this a known problem or is it most likely the seal?

[Spydaman]

According to Uncle Haynes it's relatively easy and yes I would do the cam belt at the same time. Problem is the car is in Kent and I'm in Ringwood.