Yep thats how much they can cost. Most expensive I've seen was around £60 mark last year on EBay UK. Miele charge £45 for them but there is a German seller on EBay UK who sells and sends to the UK as far as Im aware.
One thought on the SEB228/SEB236 effectiveness dispute: the SEB228 (Wessel Werk EBK360) has manual height adjustment. A lot of people think this is inconvenient, but the consensus - such as it is - is that manual height adjustment cleans better.
I haven't used the SEB236 (or its rough equivalent, the Wessel Werk EBK340) much, but IMHO the EBK360 is really, really good despite the adjustment pedal being a little stiff. Maybe that accounts for the price versus ratings disparity?