"The Screwfix telephone extension kit beats the high street DIY kits hollow: better quality wiring (solid copper, not cheap stranded copper or poor quality metal). Better connections (IDC rather than screw terminals). You don't need scissors for opening the package and best of all, IT WORKS. And this quality actually cost less than the "gift wrapped" specimen from your local DIY."
"This gave me the extension cable and socket I needed at a very good price, far cheaper than buying all of the parts separately. The cable supplied in the kit contained different coloured wires to the instruction leaflet. An e.mail to the manufacturers soon had the correct details to hand. This is no fault of Screwfix though."
"The piggy-back plug cable wiring was incorrect. Not a problem to me as I was not intending to use the piggy-back plug in the final installation. Found fault when using piggy-back plug in a test prior to cutting cable for hardwiring. Inspection showed miswiring on the piggy-back unit.
The box is fine, the cable is nice to handle and cable clips appropriate for cable.
I used a metal IDC tool so cannot comment on the included plastic one.