not enough info on uk products

[monthehoops]

i know this question has been asked a lot as ive searched the forum top to bottom,but im going to ask it again as no one is ever had a straight answer.my pal swim has googled it he has searched every main hardware store in the uk yet swim still cant find a relyable sorce for naptha.swim told me that painting,woodcare and finishing products dont say on the bottle/tub what the contents are,infact the only thing he could find that contains naptha is turpentine but how much is in it and what else....also swim noticed that even thow he can find lots of types of lighter fuel the contents are not marked on the can.swim says hes gonna get a tub of it anyway just to see if he can evaporate it and if anything is left over.would this be an indication of clean extractable naptha...