I know the UK law rules out pepper spray, but are 'home recipes' legal?

No, still illegal.

Section 5(1) (b) of the firearms act 1968, clearly states it's an offence to use anything that will discharge a 'noxious liquid'. My interpretation of that would include home made reciepes would be covered under this.

Although, i totally agree pepper spray needs to be legalised over here.

If you use anything to spray into a persons face including hairspray it then becomes an item which you have used as an offencive weapon and assault, although the carrying of hair spray or perfume is legal or many other items which if used in the way for which they have been intended makes them lawful if you then use any of those products as a weapon then it becomes a crime.

I guess not but always carry a pen or sharp pencill if you use that agaisnt a mugger and stab them to death its classed as a non ofencif weapon lol hair spray would be fine too. But you never know these days I give up on law inforcement, ur not aloud to retaliate, Im sticking to my saying, if someone mugs me or trys to burgle my house I will try to kill or seriously mutilate. WE NEED TO PROTECT OUR SELFS, NOT BEING ALOUD TO PROTECT OURSELFS LEAVES ALL THE CRIMINALS THE WEAPONS AND THE LAW ABIDEING CITIZENS SCAIRED TO GO OUT

Hair spray is a good one, as is a tail comb