Vauxhall zafira b 1.7 cdti ecoflex - Clicking noise! - Carl07lewis

Searching for help having a nightmare !! Have a clicking noise coming from the fan belt area .. disappears when aux belt is removed ... garage said was tensioner or alternator.. changed tensioner first no difference! Changed alternator and the clicking went away instantly! But 2 days later the belt started squeaking randomly (only on a cold start) changed the belt squeaking stayed . about 2 weeks after that the squeaking went away and the clicking noise has returned!!! Exactly the same clicks on cold start . Disappears if I rev to 2k revs ..! Question is did I break another alternator or did changing the alternator slightly alter whatever was clicking originaly and has now returned ? .. also removed idler and A/c by putting shorter belt on - no effect on clicking so those 2 r rules out? Any ideas!!