C'mon - even Bugsy, with his heroin-induced dementia knows that Methylated Spirit is purple.
That's white spirit - cheaper, more potent and the fuel of choice for Irish Gentlemen of the Road.
No need for meths to be dyed purple, that's just a handy extra. The surgical spirit you can get at a chemist is just meths with a bit of menthol type smelly stuff. Most modern ones also contain denatonium benzoate which is the incredibly bitter stuff painted on kids nails to stop them biting their nails.Like red diesel, methylated spirit (ethanol with methanol added to make it exceedingly unpalatable) is dyed purple. Clear Meths is available but I believe a licence is needed to buy it (think industrial users rather than local alkies though).
Methylated spirit is just denatured ethanol, industrial methylated spirit (IMS) doesn't have anything in other than ethanol, methanol and a bit of water. The issue with letting people buy near-pure ethanol is they can get pissed without paying alcohol excise duties so a small amount of methanol (around 5-10% depending on which brand) is added to render the spirit poisonous. If you can't drink it you don't pay excise duty although judging from what B&Q charge for a half litre bottle it might as well be taxed.
If you have a valid reason for needing pure ethanol (various chemical analysis techniques for instance) then organisations can apply for a tax exemption and take delivery of pure stuff without paying excise. Never been involved with that other than occasionally collecting some so I have no idea what legal hoops have to be jumped through.