Hi Les,
This isn't a Thosea as the larvae of this genus don't have the fancy spines. Can't rule out Setora. However, I'd recommend awaiting this one's eclosion until sending a record to the BMNH's Hosts database. Also keep a full record, with photos and morphometric data, so that you can write up the observations and publish in a journal on natural history / Lepidoptera somewhere.
cheers, Roger.