I have briefly seen the small rig L bracket, but I still think it's still over priced for what it is. There are a few on Ebay for around the £20 mark which I'm looking in to but it just depends on the fitment and quality.
Ebay item 223318948525
Thank you for the attached thread to dp, it has pointed out the Sirui ty-c10 qr plate that mounts to the ftz adaptor which I didn't think would be a problem until now.