Hi has anyone any ideas how to repair the washroom back panel that has come away from the floor panel it's not damp just separated in one corner near the toilet thanks
If panel has firm surface to push back onto then glue it back in place with exterior grab adhesive such as Evostik Serious Stuff or use PU adhesive/sealant such as PU18 or Tigerseal.
Or as a last resort (if the glue method doesn't work), if the washroom has fitted carpet you could always screw a corner bracket to the panel and floor and hide the one side under the carpet.
I would doubt very much that this isnt the result of damp at one time or another.
I would check there is decent wood to screw to first the floor doesnt drop for no reason sorry to say.
If you are going to use the bracket method then the best solution is to buy some round dowel rod (about 8mm. diameter and drill the wallboard to accommodate the dowels. Measure the depth of the holes to outer skin and cut the dowels to suit and glue them in with a good bonding adhesive such as 'No More Nails' or similar and leave overnight to cure. This will give a good base to screw in to and will be a permanent fix as well. The floor doesn't need the same approach as the wood is thick enough to grab the fixing screws.
This is what I did to fix a window blind surround as the old fixing holes were worn and failed to hold the frame in postion and after trying several methods first this was the best fix.