I've been looking at doing something similar, but you are a little more avios rich than us.

With 400k+ avios there may be a better (but slightly more complicated) option. That should be enough to travel using the Oneworld multi-partner award chart.

it means using at least 2 different oneworld airlines other than BA (like Qatar & Qantas). It is done strictly on miles flown, so you could tack on flights to NZ for example. It would mean not using your 241 voucher but it does mean you can fly Qatar if you want.

Anyway, I'm no expert (though managed to book one a year or so ago) but could be perfect for you.

Here's a good explanation from Head for Points:

https://www.headforpoints.com/2020/1...-flight-chart/