'99 CLK ABS Pump leaking

[r6blacky]

My CLK has been diagnosed with a leaking ABS Pump and it seems that a replacement part from Mercedes is £1137 + VAT. I believe that the part number I need is A0034319612 but I'm not sure what the situation is with regard to the ECU that's attached to the pump. Can I buy a replacement (used) pump from ebay and attach it to the ecu on the car at the moment or can the parts not be seperated?

Any help, advice would be really appreciated.

Thanks

Chris