Can anyone identify this 433Mhz OOK protocol?
"I suspect this protocol has been used for a while and may have a name." (highlighting by me)  


Possibly, but I doubt it. There's a huge chance that this is a proprietary protocol which is only internally documented. Main reasons for a proprietary protocol:  


Design freedom. The designer checked a number of existing protocols and dismissed all of them because of some technical reason or other. It may have too little throughput, or be too complex to code in a 2kB microcontroller.
Commercial protection. Use a proprietary protocol and competitors can't make products which can be used with yours, so the customer has to come back to you. Simple protocols can be reverse engineered, though, so they may want IP protection (to the extent possible, I'm not a lawyer.)


There is a zillion of those proprietary protocols around, often by small businesses who are doing their own thing and don't have to comply with anything as far as standard protocols are concerned.  

You may have a chance with reverse engineering. You don't say what kind of data the transceivers take, but maybe you could find a pattern in how a given input is coded.