Congratulations on scoring this great old rifle!

It's a BSA commercial sporter from the 1920s. The F2009 and WR19865 markings were not put there by BSA. They are likely registry marks applied in South Africa.

Is there a number stamped on the top-rear flat part of the action, where the bolt slides in?
Anything stamped on the bolt handle or the bottom of the cocking piece?

If you're planning to remove the wood, there may be some marks underneath the fore-end that can tell us more.

The rifle is a genuine commercial sporter (not a military conversion), but whether it qualifies as a "Lee Speed" depends on how you use the term. "Lee Speed Patents" is not a model name; it is a patent acknowledgement. After a certain time, the patents ran out and the stamp ceased to appear, but the rifle details (in many cases) did not change. So was it really a different rifle, even without the stamp? I would say no, but many collectors will disagree (which is fine by me).