SAS SOLDIER X or Z books (Swindon SN6)

Hi, We are looking for the SAS Soldier books. We have A-W & Y, but we are still missing X & Z to complete the collection series for my wife's dad. Hopefully, someone has them and is willing to part with them. We are also happy to take another complete A-Z set, as there is another veteran gentleman who wishes to have a set for himself also.