As per title we’re looking to stay in London for around a week this Autumn. In exchange, it might be your chance to discover Palermo and Sicily, soak up some sun and indulge in some gelato 
We’re 2, we prefer locations not too far from London city center.
Welcome to the Forum! 
A week in Palermo in Autumn sounds like heaven. I’m sure you’ll have no problem finding a swap! Have you tried a reverse search? I’m sure there will be many in London interested in Sicily. https://help.homeexchange.com/hc/en-us/articles/360000730557-What-is-reverse-search-and-how-do-I-use-it
@Melissa.HomeExchange thanks Melissa this feature looks super helpful!
Yes it can be super helpful when looking for somewhere specific Your location is a popular spot so i’m sure it will help!