Hi Ian, We switched our spec to Wylex NM range following the introduction of 18th Edition. Manufacturer wise we have used Wylex for a lot of years with few issues. We are now fitting RCBO’s to all circuits except cooker and Shower circuits which we are fitting AFDD’s to, the logic being that these appeared to be the greatest risk in terms of loose connections etc. certainly in my experience as an Electrician, I found this to be the case in Shower pull switches on a number of occasions. We also have SPD’s as standard, trying to record and demonstrate a risk assessment to evidence the rare occasion that we didn’t need them seemed pointless.