I have fitted a Plasson reducing coupler 20 x 25 with a conversion set. Joining a 20mm MPDE pipe for an outdoor tap to a 22mm HEP2O pipe (rising mains). The Plasson items are below: Reducing Coupling 25 × 20: http://www.plasson.co.uk/catalogue/product/4425 Conversion Set for Copper Pipe 25 × 22:http://www.plasson.co.uk/catalogue/product/4702 Annotated pic: https://e.pcloud.link/publink/show?code=XZrR0XZkwYPR3xx0fuIaU6qUvuoPkvecdK7 From the conversion set, the aluminium gripping teeth are very difficult to move up the HEP2O pipe and slightly scratch the pipe. I know of a plumber who got this Plasson product working with HEP2O pipe. Not sure how. Should I use, instead of the Plasson coupler, a push fit kit from Plasson instead (below)? Female Adaptor 20 × 3/4″: http://www.plasson.co.uk/catalogue/product/4495 Copper Pipe Male Adaptor 22 × 3/4″: http://www.plasson.co.uk/catalogue/product/9173