...I'm not sure if Meths is safe to clean wounds with (chemically speaking).
Alcohol has long been used to sterilise things not sure if Meths is safe to do the same? anyone know?
Meths and surgical spirits (surgical alcohol/rubbing alcohol) are basically the same thing, at least in the UK. That is they're both ethyl alcohol with something (usually methyl alcohol) added to denature it so that it's undrinkable. In the USA they tend to use isopropyl alcohol (IPA, de-icer, whatever) as rubbing alcohol instead of meths. IPA is undrinkable anyway, so it doesn't need denaturing.
From the point of view of emergency treatment for cleaning a wound I wouldn't hesitate to use meths or IPA instead of surgical alcohol if that was all I had, although I always have a little bottle of surgical alcohol in my FAK. For long term use such as hardening skin, for walking, playing the guitar etc., I'd be reluctant to use something which wasn't intended for use on the skin. All these products are highly flammable, and a meths flame can be difficult to see, so care is needed. There have been terrible fires in operating theatres involving surgical alcohol.
Products sold as surgical alcohol will be guaranteed free of carcinogenic contaminants such as traces of benzine. Products sold for use as fuels might not be. Years ago when I worked with explosives we used alcohols a lot as solvents and for cleaning. My boss used to buy the alcohols. There was 95% ethanol and 99.9% ethanol, and he preferred the 95%. The 99.9% was distilled from benzine, and so it was dangerously toxic, but the 95% was distilled from brewed products and it was (allegedly!) drinkable. At least it had duty on it courtesy of Customs & Excise, which the 99.9% didn't. I never did find out if he was actually drinking the stuff, and I never tried it myself.