water leak after replacing head gasket

[juz22]

i've replaced my head gasket and after refitting everything upon first starting it have a coolant leak from the transmission side of the engine.

i was in a rush when testing it so made a quick video and then swiftly turned the engine off. i couldn't see any obvious split hoses. the water seemed to be flowing onto the flywheel from somewhere? any ideas what could be the cause? thanks