Bother, I've got egg on my face this time, well and truly.  I bought a KF4 Swissgold 12-cup permanent filter home tonight to drop into the Sainsbury's filter coffee machine and guess what; it didn't fit.  So I pulled out the insert that the factory filter sat in (top image, with factory filter; note again, this filter was white and has discoloured to the extent shown after just one brew cycle), and while i could just get the door to close if I held it all just so as I closed the filter door on the machine I would not recommend this machine as being suitable for the KF4 Swissgold replacement filter (lower image).

Anyway, I've loaded the filter machine with water for the morning, so all it requires is 45g of coffee ground on the same setting as the test we ran earlier today (Tuesday 28 Dec).  I think the life expectancy of this machine in our household has just been reduced somewhat as the ill fitting KF4 Swissgold filter in this machine is going to bug me more and more each time I use it.  You get what you pay for I guess.  The fit is so close, but not quite, that I'd even suggest the manufacture may have deliberately sized the recess to make it difficult for after-market filters like the Swissgold to be fitted.

Oh well, if nothing else it has taught me to be more sympathetic if customers purchase a KF4 Swissgold filter from us and have a similar experience.  As long as you return the filter undamaged in its box we will promptly refund you in full