Hi mate oil leaks are horrible well it's really hard to tell what the fluid is hard to tell from the pictures could gear oil, brake fluid or engine oil
Could be
If it's :
Gear oil - Input shaft seal, detemps
Brake fluid - leaking slave cylinder or pipe
Engine oil - rear crank seal
If it's defo coming from where the bell housing meets the engine and not any higher I would say box has to come out ;(