Cheers Hutch, I've been trying that but did'nt want to force it. I'll have another go.Hi there, removal of the pipes, if you push in the smaller"collar" towards the connector it will go in all the way and the pipe will pull out of the fitting. On fitment push the pipe as far in as it will go and then slowly pull it out and that little collar will come out maybe 1/8th of an inch and then lock the pipe.
I have never had to replace a cartridge so someone else will tell both of us how to do it.