Miele G646 SC Plus leaking from circulation pump

I noticed last night (after taking the machine apart) that the circulation pump was leaking (dripping).

I had a PDF of parts from Miele and notice that the pump comes in three separate parts, the pump itself and two plastic parts which seem to unscrew.

Both these parts have a rubber seal, which I assume (as I haven’t taken the pump out yet) that have degraded. However Miele do not seem to sell the seals on their own but as part of a kit, which is rather expensive.

Can you obtain the seals themselves without the counter parts? What does anyone suggest to narrow down which component is actually causing the leak?

Is there anything special I need to conceder when removing the pump?