God, you lot are so quick.......... it's hard to keep up with you all ;-)
Boswell Bros USA=nothing to do with us at all, ever. The circuses in america are 'framed' around whatever name the management think will do some good.
Boswell-Wilkie [www.circus.co.za] no longer run a travelling circus. It came about when Boswell Bros sold to African Theatres in the 1960s and then amalgamated with WH Wilkie's circus (from England). The case at
http://www.saflii.org.za/za/cases/ZASCA/1985/64.html was when we went out as Brian Boswell's Circus in 1982 and Wilkie took us to court to stop us using the name Boswell. We traded as 'Brians Circus' until 2004 when we reverted to Brian Boswell's Circus and Wilkie's heirs didn't have the wherewithall to stop us. The case is still used as precedent in SA Law.
The picture in your avatar was probably taken April 27 to May 2 1903 (the larger version has a zebra in it ;-) so Lyle was in SA by then, did her family follow later? Walter and Lyle were together in the UK in 1939 but you reckon she and Thelma had left to go back to live there during the 1930s?
When you say "She had a brother also named John Henry Marr. She was the first born in a large family, so probably the father was born roughly 20 years earlier (just guessing). Other siblings: Thomas, Albert, Herbert?, Nellie, William, Lilly, Frank, possibly others, some others died in childhood." from where do you draw this information? For her and her husband Walter to both have relatives Nellie and Lilly is a coincidence (but not impossible ;-)
very best
Jim