Vauxhall Corsa

[OAP man]

I have a 2012 Vauxhall Corsa sri which has done 45,000 miles. It has recently started making a ticking noise but only between 1,500 and 2,000 RPM when accelerating. If the car is in 3rd gear at 1,500RPM, and then l accelerate the engine is under more load due to the high gear and the noise is more pronounced. My local garage said these engines are ratttley anyway and recommended I try Wynns "Super Charge" oil additive but this has only slightly reduced the ticking. Any idea if the underlying problem is more serious than a rattley engine