Led dimmers flickering

Not the normal senario. I went with my mate to look at a job we first wired over 15 years ago. Multi million £ house in central London. All the lighting is wired through 'Powerhouse X10 dimmers or controllers'. The circuits we have problems with  have recently had halogen GU10's  replaced with GU10 Led's, we have tried a few different makes. 

This system has remote mounted din rail controllers and retractive switches (some rooms with 3 switches each circuit per room) which turn off/on & dim. All  the halogen  light bulbs have been replaced with Led's due to the new EPC rules.

When turned  off we are getting 13.5v at the lamps most of  the time  & this is dimly  lighting one of the lamps per switch circuit. Swapping out different makes of lamp makes the one that is lit move around (i assume to the one with the lowest resistance) when swapping out a Led for halogen this clears the  glow. This makes me think its inductive but 13.5v ???  We have tried Danlers caploads which stop the glow but put terrible flicker and noise that is not acceptable . Leaving 1 halogen per switch is not acceptable. Danlers Resload wont work due to the heat and accessiblity . The X10 appears not made anymore. 

Any help, recomendations for replacement or repair please

Have you tried ZANO ? I have found them very helpful

Snubber?

The Resload is a snubber.  I had a look and Zano make exactly what we are looking for so will be swapping out the X10's