Thanks for your advice.
Yes the issue was the Top LHS wishbone fitted last August and only driven less than 3K since it was changed. After complaining about the noise from the left hand side the Alfa Specialist changed both front springs and struts. Problem still the same so changed LHS roll bar link that was found very stick or notchy.
After the link changed the noise was unbearable so mechanic had another go and this time found top LHS wishbone at fault.
All along I had believed there was a fault but the Alfa Specialist could find nothing. So after more than six months of misery, a change of springs/struts, a change of a roll bar link that was changed less than 2000 miles ago I know have the problem solved by simply changing a top LHS wishbone that must have been fitted incorrectly last August.
I pointed out to the engineer last August after the suspension work that a noise existed on the left hand side. I noticed the noise immediately afetr driving the car away from the garage. I retuned to the mechanic 1 hour later and complained. The mechanic told me that the bolts on the LHS wishbone had not been fully tightened and by tightening the bolts should cure the problem.
Well, as far as I am concerned, the poorly fitted replacement wishbone last August gave way to wear and tear on the LHS roll bar link and premature wear on the Wishbone. It looks to me that if the work last August had been carried out properly then the inconvenience and subsequent additional costs I have incurred during tha past 6 months would not have been necessary.
Well at least I am happy with the front end and pleasure has been brought back into driving my 156.