ARK has phalanx on her port quarter (with a white dome on top of the gun); LUSTY has Goalkeeper, a much larger weapon system with the mount on a raised level. Stick the phot on here and us ship spotters can help you out!!!
When you add your next post to the thread, look at the two rows of icons above the blank space for your typing. Bottom row, far left, is an icon which looks like two mountains with the sun rising behind them. Hover over it and you will see the word "Image". Click on it: A little window opens asking you to "Please enter image URL".
If you copy and paste your photo's URL into that window, we should be able to see your pic.
I led myself and others on a wild goose chase for a while. It appears I have photographed all three carriers.
The first shot is Invincible and HMS Nottingham.
Next is Invincible and the decommissioned HMS Exeter. There is no carrier alongside Invincible.
Next is Invincible and HMS Edinburgh
The final shot is my questioned photo. It appears we have Ark Royal to the right, because of the Phalanx. But the carrier to the left in that photo must be Illustrious. It appears to have white canvas on it similar to the shot of the Illustrious on 12 August posted by Naval_Gazer.