Autotrail Mohawk fresh water tank drain. Went to turn tap back off ready to fill it for the weekend out and tap was so stiff it turned pipe underneath and pipe and tap came out in one. Obviously need new tap but what holds it in the other end. It appears to be a 25mm reducer on the 28mm pipe but I can only see flexible outlet on tank not a solid as far as i can see without grovelling underneath. Anyone any suggestions to save an 84 year old from going underneath to investigate ??? I did refit it yesterday with silicone seal but it came adrift this morning again.