The cold feed in my bungalow is black alkathene pipe, with copper spurs off to different appliances. I need to replace everyting in the bathroom. My question is what sort of compression fittings do u use to connect to this type of pipe. the existing ones appear to be 3/4in, seem very old. Do u use ordinary 22mm connectors with 3/4 olives, if so how do u make sure u get a good tight fit. Any suggestions would be apprecited