Styrene is not that hard to come by ;)
How about converting it to benzaldehyde
Patent GB774608 (http://l2.espacenet.com/dips/viewer?PN=GB774608&CY=gb&LG=en&DB=EPD)
(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000315438-file_qhyy.jpg)
Unfortunately the yields aren't as good as those given here :
https://www.thevespiary.org/rhodium/Rhodium/chemistry/benzaldehydes.kmno4.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/benzaldehydes.kmno4.html)
John Lennon - Working Class Hero