I am making bath fizzy bombs and the recipe requires corn starch Do you think cornflour would be ok to substitute for this?

Cornflour (also known as cornstarch in some countries) is a fine powder made from the endosperm of maize (corn). It is used as a thickening agent in cooking and baking and as an ingredient in cosmetics and adhesives.

Cornstarch and cornflour are essentially the same product, differing only in regional naming conventions. In the United States, the term "cornstarch" is commonly used, while in the United Kingdom and many other countries, "cornflour" is preferred. Both terms refer to the same maize-derived powder.

Therefore, using cornflour as a substitute for cornstarch in making bath bombs should be perfectly fine. It will serve the same purpose as a thickening agent and provide the desired consistency to the mixture.