You know what...this is pure coincidence!! I nearly made a post last night on the exact same topic.
When i got my F about 1 month ago, I spent £60 on Maguiers products. Last night gave it a quick wash with water and fairy liquid and then a polish with parents turtle wax (£3 a bottle (label still on bottle!!)) Was well impressed, i am seriously wondering why I spent all that on the maguiers!!
Chris.....I'm not 100% sure but I think using fairy liquid on your car is a bad idea. The reason for this is that it is a different type of detergent to car shampoo. It can cause dullness of the paint as it is formulated differently.
I think because you have only done it once and then polished you should be ok but I wouldn't reccommend doing this again.