That's really funny. I only just posted this to Russell's BBC BASIC repository yesterday.
https://github.com/rtrussell/BBCSDL/issues/12
The version of BBC BASIC in Russell's repository may be a better one to use for the ESP32 as it is already 32bit.
I'm not sure that I have the skills at the moment to complete this activity, but I will support someone who has in any way that I can.