RE: MORNING ALL23 Oct 2019 14:44
NK, in my opinion what i would do is clean all the joint areas, this must be done very thoroughly so any existing sealant that has been applied is removed all around the shower base tray that fix to the cubicle enclosure also any parts of the cubicle that are attached to the wall.
Once this is done you need to make sure all the cleaned areas are perfectly dry, then you will need a tube of either clear or coloured shower sealant that matches the tilling and a mastic gun for application to reseal the entire cubicle.
It must be SHOWER sealant not any ordinary cheap mastic.
As someone already mentioned it would also be worth cleaning around the drain outlet and reseal this at the same time.
Just a quick question are the pipes that feed the shower accessible at all as these would also be worth checking.
Sorry i cant help more than that, but hope you manage to sort it out.