Wilc doesn't strike me as the type that enjoys pulling things apart so dare i suggest he pops down to halfords and gets transmission leak stop and coolant leak stop , i know the magic fix is frowned upon but i bought a new seal for my front diff and not having time to replace it before the Romania trip i stuck some leak stop in there and left on a wing and a prayer . 5000 miles later its still bone dry .
Get what you're saying Shayne but I think he really needs to find the source of the problem, leak stop isn't a fix it's just a way of hiding the problem.
Appreciate it's working for you but as you're going to change the seal anyway it's not really comparable, Wilc doesn't know what the problem is so can't use it as stop gap until he gets a chance to properly repair and to do that he needs to know the cause in the first place.