Hi Alex,
Its a great bridge and a shame to pull down. Looks like theres a bit of interest which might help but like most old iconic constuctions they get bulldozed then everyone starts talking about heritage listing.
There's some old railway bridges near me that are still intact.
Theres also this site which is sort of what you need to get the info out there.
http://abandonedbutnotforgotten1.blogspolt .com/2015/12/wimmera-river-bridge-at-quantong.html
Good luck.
Andy