I went through this years ago. Got a 'professional' to measure and fit a replacement liner and make sure any holes in the sand floor were filled. That was his biggest problem. Well, after 3 goes (that's 3 pools filled and emptied again) he did his nana and just slashed his liner out and buggered off!! I measured it, ordered it and installed it without drama. I think a QLD company did the welding but I've forgotten the details, sorry. It's not a hard job, just take your time and do it in warm weather.