For those who have the Separ Filter SWK-2000/5 unit, element p.no. 00530.
The elements cost £20.13 each from Marine Power, however, from SVB Hamburg P. No. 67004 Euro 16.90. With current exchange rates this is approx £14. Even with postage still cheaper than UK, esp. if you buy other items !?
My experience of SVB, having bought items from them is that they are helpful, and ship promptly