Ah, that grapefruit/pineapple combo, so beloved by people in the UK until – when? When did we stop drinking Lilt? It is still available but has somehow slipped out of the national consciousness. I use it here, or, when possible, use Ting instead. Ting is a grapefruit-flavoured soft drink from the Caribbean which can be found in some supermarkets and Caribbean grocery stores. I love it – it’s not as sweet as a lot of soft drinks and is excellent in a shandy. The ham/fizzy drink combo isn’t unprecedented. People (including, of course, Nigella Lawson) have been cooking ham in cola for years. I like the close, dense texture it produces for the ham, and the cooking liquor is a very good base for a black bean soup.
If frying sweetcorn fritters as well as grilling fruit is a bit of a stretch, you can always use the same ingredients and make a salsa instead. Toast the sweetcorn in a pan until lightly charred, then add the rest of the vegetables and seasonings and a dash of soy sauce, oil and lime juice. This can be done in advance.