I ended up using an extra half cup of oat flour and 225g of black beans.
My experience with bean burgers fried has always been a disaster so I cooked them in the air fryer, 10 minutes at 200 then flip and cook for 5. I made big fat ones, I guess slimmer ones would be quicker.
For me, these tasted like black pudding and with a bit of all spice, they could pretty much pass for it. Tasted good though, maybe a bit dry, but nothing an avacado or a juicy tomato couldn't solve.