I hadn't heard of this before so, here's a quote from a site as to what it is:
Enhancer contains 1kg of a blend of spray dried dextrose and spray dried malt extract which is simply added in place of sugar to any beer kit. It enhances the natural flavour of the kit
It looks to me like it's just corn sugar and DME. Depending on what kind of "sugar" it's replacing, it may change the flavor from what the recipe intended. If there was a reason to use it, you could just make this yourself for a lot cheaper.
For any sugar in my UK ales, I like Lyle's Golden Syrup.