Mystery solved: It's the tender to Avantage. https://www.compasstenders.com/portfolio_page/limousine-tender-10-0m/
You do not see alot of "Topaz" (now "A+") tenders. Here is her Guest convertible sports tender by Vikal.
I've read on the latest issue of a well-known yachting magazine that Tim Heywood designed one of the Flying Fox's tenders. Could it be the Yachtwerft Meyer Limousine? It doesn't look like the typical Heywood design but you never know.