Would it be OK to substitute Lyle's Golden Syrup for Corn Syrup?

Yes, I have tested it with Lyle's Golden and it works well. They are slightly softer though and I refrigerate them.

Thanks, hardlikearmour, for a much more thorough answer than mine!

Lyles is partially inverted syrup - meaning it's a combination of sucrose syrup with glucose and fructose. It's less likely to crystallize than pure sucrose (i.e. common sugar), but it's not as inverted as corn syrup so there will be a greater risk of your caramels crystallizing. I'd consider adding the lemon juice with the sugar and syrup to help invert more of the sucrose to help prevent problems. I also like cooking these caramels to 244º or 245º - they're a little soft at 240º IMO.

Yes, it should be fine.