Re: Well someone's been on a heavy drinking session
"as any fule kno, it is the ABV strength of each drink that is a factor"
I got to disagree there. According to my 'research', the major factor besides is the absolute quantity of alcohol, whether it's 10 beers or 10 glasses of wine or 10 tots of whisky is the same.
Next factor is the quality. The cheapo bottom-shelf whisky has the same alcohol content as a single malt or even a quality blended whisky, but will give a much worse headache / hangover. Lack of other non-alcohol ingredients / impurities means the liver can focus on processing just the alcohol and not other crap (in this respect, generally good fitness / diet also helps). Incidentally, many drinks considered 'nasty' for cheapo-drinking students (eg vodka or tequila) have quality, albeit expensive, equivalents that are the equivalents of single malts in Russia / Poland, Mexico etc
The other thing that works for me to avoid hangovers is alternate a glass of water in between each alcoholic drink. This both keeps the body hydrated as well as spacing out drinks to reduce the absolute amount of alcohol. Carbonated drinks don't work so well in this respect (liver also needs to process caffeine in colas and other crap in fizzy drinks). Sports drinks might work as well.
In all cases stay away from anything fluorescent-looking