Mark wrote:
Can anyone recommend any safety specs that do not fog up? (I've tried
treating the glasses with washing up liquid and various anti fog
treatments, but they are not very effective).

Somewhere recently I saw a battery-powered helmet contraption with a
visor; a fan drew in air and blew it down inside over your face,
removing the water vapour which causes the fogging. Can't remember
where I saw it though I'm afraid - thought it was Screwfix, but I can't
locate it!

David