You could try the Campden pasteurisation guide as a starting point?
Whether it contains any data that you'd be able to demonstrate is applicable to your product is a more difficult question though, as it is understandably focussed on relatively mainstream/standard products/materials and the latest edition is from 2006, so pre-dates the rapid growth in "plant based" products.
Would I be correct in assuming that your product is some sort of meat substitute?
The USDA has some guidelines on meat processing that may possibly also be a useful reference point: https://www.fsis.usd...AND POULTRY.doc
As nlamers indicates, there is no specific time/temperature requirement for this, at least in the UK (I'm assuming you're in the UK based on the use of Campden), so your general obligation is to produce safe food.
The overall process is interesting as it's almost akin to hot-fill, but done in two steps. As such I suspect that a lower thermal treatment for the packing step could well be viable as you'll presumably have validated the initial cook for suitably addressing micro hazards in the product itself.
At risk of asking a stupid question - if the packaging will tolerate 80°C, would it also tolerate the extra 10°C for the cook, such that you could perhaps combine into one step and cook the product in pack, avoiding the need for the second thermal process?