Low-grade hash is referred to as 'solid' or 'sput'
The latter, for some reason, short for 'sputnik' Where that one came from, etymologically speakig, I haven't a clue.
'Whitey'-this is what happens when somebody smokes more weed than they can handle, so called, because along with their head spinning, feeling dizzy and overwhelmed, their face turns ghostly pale. Usage as follows 'he/she pulled a whitey' or 'he popped a whitey after his first bong, what a lightweight'.
Chav-there are many backronyms, acronyms and false etymologies for this term. What it describes, is a typically teenage (although they can be any age), snot-nosed little oik. Tends to hang around in large crowds of their fellow verminous hood-rat trash breed, to facillitate such activities as mugging people, swilling cheap lager (and subsequently getting into fights, and/or vomiting in the street)
They act hard and when with their pack, but get one on their own, and they are invariably fucking pussywhipped little bitches.
Also-charver, pikey, chavscum, scally.
There are tons of folk etymologies for these little shits. Such as 'council house and violent' for insance, as one of the more amusing ones. So far as I know though, its thought likely to come from the romanian 'chavi' meaning 'boy'
Gat-handgun
Battyman/batty bwoy-I don't think this is strictly local, but it originates from jamaican patois, meaning 'puff/faggot'