Fresh Water Tank Problem

We are in Mazatlán  Mexico and have encountered a problem, leak, in the fresh water tank.  The roads on the way down were a little bumpy and during the travels I began to notice a small drip from the rear underside of the fifthwheel, a 2015 Lfestyle LS38RS.  I removed the fabric membrane and exposed the tank.  I found that one of the self tapping screws used to hold the fabric  in place had rubbed on the bottom side of the tank and created a small hole.  The tank likely shifted around due to the bumps and came into contact with the  screw tip.

I have installed an expansion plug into the tank, glued it, and placed Ether bond tape over over the entire area.  Leak has stopped hopefully long enough for us to finish the winter and return to the US for repairs.

Has anyone had luck with plastic welding?  Is there a source for a new tank, or any other options available for repairs/replacement that others have had success with?

Thanks in advance for any information!!

PS the weather here is fantastic, walking the beach daily and swimming in the ocean to cool off.  There are two Carriage fifthwheel in the park and will make sure they know about the forum.