JK, I agree with you 100%. FAIRY Liquid will not restore the colour.
Is only to get all the dirt and grime off the tubes using a mild detergent which has also some short of a polishing agent in it.
However, the ARMORALL will though.
Something whioch I forgot. With the above method shine or colour restoration does not last (only for 5-7 days the very max). Is a cheap cheap way to polish your boat if you don't want to change the tubes. I have tested it and worked for me in the past