Hi Guys, we need to replace our 3 port tower valve but there is so much choice we really need your advice. Which is the best make and model to buy for long term reliablility. Honeywell V4073 seems to be the most common but we have also seen the Tower VAL322MP, Potterton myson mpe322 and acl Drayton MA1/679. All your help to choose the best will be much appreciated. Thanks jayne