Cheers everyone
I was using malt vinegar (acv practically doesn't exist in the UK.)
1. Pour a few pint glasses of water over head.
2. Pour a pint of water with some baking soda over head and rub in a little.
3. Wait around 20 mins.
4. Pour a few pint glasses of water over head.
5. Pour a pint of water with a few splashes of malt vinegar in over head and rub in a little.
6. Wait around 5 mins.
7. Pour a few pint glasses of water over head.